diff --git a/libraries/gptUtils/gptUtils.js b/libraries/gptUtils/gptUtils.js
index 17ca64483ab..21310ac7b5b 100644
--- a/libraries/gptUtils/gptUtils.js
+++ b/libraries/gptUtils/gptUtils.js
@@ -1,5 +1,5 @@
 import { CLIENT_SECTIONS } from '../../src/fpd/oneClient.js';
-import {compareCodeAndSlot, deepAccess, isGptPubadsDefined, uniques, isEmpty} from '../../src/utils.js';
+import {deepAccess, isGptPubadsDefined, uniques, isEmpty, isAdUnitCodeMatchingSlot} from '../../src/utils.js';
 
 const slotInfoCache = new Map();
 
@@ -13,7 +13,10 @@ export function clearSlotInfoCache() {
  * @return {function} filter function
  */
 export function isSlotMatchingAdUnitCode(adUnitCode) {
-  return (slot) => compareCodeAndSlot(slot, adUnitCode);
+  return (slot) => {
+    const match = isAdUnitCodeMatchingSlot(slot);
+    return match(adUnitCode);
+  }
 }
 
 /**
@@ -35,7 +38,10 @@ export function getGptSlotForAdUnitCode(adUnitCode) {
   let matchingSlot;
   if (isGptPubadsDefined()) {
     // find the first matching gpt slot on the page
-    matchingSlot = window.googletag.pubads().getSlots().find(isSlotMatchingAdUnitCode(adUnitCode));
+    matchingSlot = window.googletag.pubads().getSlots().find(slot => {
+      const match = isAdUnitCodeMatchingSlot(slot);
+      return match(adUnitCode);
+    });
   }
   return matchingSlot;
 }
diff --git a/modules/bidViewability.js b/modules/bidViewability.js
index f1acc6096cc..2c09c60748d 100644
--- a/modules/bidViewability.js
+++ b/modules/bidViewability.js
@@ -5,7 +5,7 @@
 import {config} from '../src/config.js';
 import * as events from '../src/events.js';
 import {EVENTS} from '../src/constants.js';
-import {isFn, logWarn, triggerPixel} from '../src/utils.js';
+import {isAdUnitCodeMatchingSlot, logWarn, triggerPixel} from '../src/utils.js';
 import {getGlobal} from '../src/prebidGlobal.js';
 import adapterManager, {gppDataHandler, uspDataHandler} from '../src/adapterManager.js';
 import {gdprParams} from '../libraries/dfpUtils/dfpUtils.js';
@@ -13,20 +13,14 @@ import {gdprParams} from '../libraries/dfpUtils/dfpUtils.js';
 const MODULE_NAME = 'bidViewability';
 const CONFIG_ENABLED = 'enabled';
 const CONFIG_FIRE_PIXELS = 'firePixels';
-const CONFIG_CUSTOM_MATCH = 'customMatchFunction';
 const BID_VURL_ARRAY = 'vurls';
 const GPT_IMPRESSION_VIEWABLE_EVENT = 'impressionViewable';
 
-export const isBidAdUnitCodeMatchingSlot = (bid, slot) => {
-  return (slot.getAdUnitPath() === bid.adUnitCode || slot.getSlotElementId() === bid.adUnitCode);
-}
-
-export const getMatchingWinningBidForGPTSlot = (globalModuleConfig, slot) => {
+export const getMatchingWinningBidForGPTSlot = (slot) => {
+  const match = isAdUnitCodeMatchingSlot(slot);
   return getGlobal().getAllWinningBids().find(
     // supports custom match function from config
-    bid => isFn(globalModuleConfig[CONFIG_CUSTOM_MATCH])
-      ? globalModuleConfig[CONFIG_CUSTOM_MATCH](bid, slot)
-      : isBidAdUnitCodeMatchingSlot(bid, slot)
+    ({ adUnitCode }) => match(adUnitCode)
   ) || null;
 };
 
@@ -63,7 +57,7 @@ export const logWinningBidNotFound = (slot) => {
 
 export const impressionViewableHandler = (globalModuleConfig, event) => {
   const slot = event.slot;
-  const respectiveBid = getMatchingWinningBidForGPTSlot(globalModuleConfig, slot);
+  const respectiveBid = getMatchingWinningBidForGPTSlot(slot);
 
   if (respectiveBid === null) {
     logWinningBidNotFound(slot);
diff --git a/modules/bidViewability.md b/modules/bidViewability.md
index 922a4a9def4..24f7dcd019e 100644
--- a/modules/bidViewability.md
+++ b/modules/bidViewability.md
@@ -12,7 +12,7 @@ Maintainer: harshad.mane@pubmatic.com
 - GPT API is used to find when a bid is viewable, https://developers.google.com/publisher-tag/reference#googletag.events.impressionviewableevent . This event is fired when an impression becomes viewable, according to the Active View criteria.
 Refer: https://support.google.com/admanager/answer/4524488
 - This module does not work with any adserver's other than GAM with GPT integration
-- Logic used to find a matching pbjs-bid for a GPT slot is ``` (slot.getAdUnitPath() === bid.adUnitCode || slot.getSlotElementId() === bid.adUnitCode) ``` this logic can be changed by using param ```customMatchFunction```
+- Logic used to find a matching pbjs-bid for a GPT slot is ``` (slot.getAdUnitPath() === bid.adUnitCode || slot.getSlotElementId() === bid.adUnitCode) ``` this logic can be changed by using config param ```customGptSlotMatching```
 - When a rendered PBJS bid is viewable the module will trigger a BID_VIEWABLE event, which can be consumed by bidders and analytics adapters
 - If the viewable bid contains a ```vurls``` param containing URL's and the Bid Viewability module is configured with ``` firePixels: true ``` then the URLs mentioned in bid.vurls will be called. Please note that GDPR and USP related parameters will be added to the given URLs
 - This module is also compatible with Prebid core's billing deferral logic, this means that bids linked to an ad unit marked with `deferBilling: true` will trigger a bid adapter's `onBidBillable` function (if present) indicating an ad slot was viewed and also billing ready (if it were deferred).
@@ -20,7 +20,6 @@ Refer: https://support.google.com/admanager/answer/4524488
 # Params
 - enabled [required] [type: boolean, default: false], when set to true, the module will emit BID_VIEWABLE when applicable
 - firePixels [optional] [type: boolean], when set to true, will fire the urls mentioned in bid.vurls which should be array of urls
-- customMatchFunction [optional] [type: function(bid, slot)], when passed this function will be used to `find` the matching winning bid for the GPT slot. Default value is ` (bid, slot) => (slot.getAdUnitPath() === bid.adUnitCode || slot.getSlotElementId() === bid.adUnitCode) `
 
 # Example of consuming BID_VIEWABLE event
 ```
diff --git a/modules/gptPreAuction.ts b/modules/gptPreAuction.ts
index db2978e1302..dedeb45202c 100644
--- a/modules/gptPreAuction.ts
+++ b/modules/gptPreAuction.ts
@@ -13,8 +13,6 @@ import {
   pick,
   uniques
 } from '../src/utils.js';
-import type {SlotMatchingFn} from '../src/targeting.ts';
-import type {AdUnitCode} from '../src/types/common.d.ts';
 import type {AdUnit} from '../src/adUnits.ts';
 
 const MODULE_NAME = 'GPT Pre-Auction';
@@ -66,8 +64,6 @@ export function getAuctionsIdsFromTargeting(targeting, am = auctionManager) {
 }
 
 export const appendGptSlots = adUnits => {
-  const { customGptSlotMatching } = _currentConfig;
-
   if (!isGptPubadsDefined()) {
     return;
   }
@@ -81,9 +77,7 @@ export const appendGptSlots = adUnits => {
   const adUnitPaths = {};
 
   window.googletag.pubads().getSlots().forEach((slot: googletag.Slot) => {
-    const matchingAdUnitCode = Object.keys(adUnitMap).find(customGptSlotMatching
-      ? customGptSlotMatching(slot)
-      : isAdUnitCodeMatchingSlot(slot));
+    const matchingAdUnitCode = Object.keys(adUnitMap).find(isAdUnitCodeMatchingSlot(slot));
 
     if (matchingAdUnitCode) {
       const path = adUnitPaths[matchingAdUnitCode] = slot.getAdUnitPath();
@@ -174,16 +168,9 @@ type GPTPreAuctionConfig = {
    */
   enabled?: boolean;
   /**
-   * If true, use default behavior for determining GPID and PbAdSlot. Defaults to false.
+   * If true, use default behavior for determining GPID. Defaults to false.
    */
   useDefaultPreAuction?: boolean;
-  customGptSlotMatching?: SlotMatchingFn;
-  /**
-   * @param adUnitCode Ad unit code
-   * @param adServerAdSlot The value of that ad unit's `ortb2Imp.ext.data.adserver.adslot`
-   * @returns pbadslot for the ad unit
-   */
-  customPbAdSlot?: (adUnitCode: AdUnitCode, adServerAdSlot: string) => string;
   /**
    * @param adUnit An ad unit object
    * @param adServerAdSlot The value of that ad unit's `ortb2Imp.ext.data.adserver.adslot`
@@ -206,8 +193,6 @@ declare module '../src/config' {
 const handleSetGptConfig = moduleConfig => {
   _currentConfig = pick(moduleConfig, [
     'enabled', enabled => enabled !== false,
-    'customGptSlotMatching', customGptSlotMatching =>
-      typeof customGptSlotMatching === 'function' && customGptSlotMatching,
     'customPreAuction', customPreAuction => typeof customPreAuction === 'function' && customPreAuction,
     'useDefaultPreAuction', useDefaultPreAuction => useDefaultPreAuction ?? true,
   ]);
diff --git a/src/prebid.ts b/src/prebid.ts
index e662a0e178c..6b30ca192ca 100644
--- a/src/prebid.ts
+++ b/src/prebid.ts
@@ -28,7 +28,7 @@ import {listenMessagesFromCreative} from './secureCreatives.js';
 import {userSync} from './userSync.js';
 import {config} from './config.js';
 import {auctionManager} from './auctionManager.js';
-import {isBidUsable, type SlotMatchingFn, targeting} from './targeting.js';
+import {isBidUsable, targeting} from './targeting.js';
 import {hook, wrapHook} from './hook.js';
 import {loadSession} from './debugging.js';
 import {storageCallbacks} from './storageManager.js';
@@ -610,14 +610,13 @@ addApiMethod('getBidResponsesForAdUnitCode', getBidResponsesForAdUnitCode);
 /**
  * Set query string targeting on one or more GPT ad units.
  * @param adUnit a single `adUnit.code` or multiple.
- * @param customSlotMatching gets a GoogleTag slot and returns a filter function for adUnitCode, so you can decide to match on either eg. return slot => { return adUnitCode => { return slot.getSlotElementId() === 'myFavoriteDivId'; } };
  */
-function setTargetingForGPTAsync(adUnit?: AdUnitCode | AdUnitCode[], customSlotMatching?: SlotMatchingFn) {
+function setTargetingForGPTAsync(adUnit?: AdUnitCode | AdUnitCode[]) {
   if (!isGptPubadsDefined()) {
     logError('window.googletag is not defined on the page');
     return;
   }
-  targeting.setTargetingForGPT(adUnit, customSlotMatching);
+  targeting.setTargetingForGPT(adUnit);
 }
 addApiMethod('setTargetingForGPTAsync', setTargetingForGPTAsync);
 
diff --git a/src/targeting.ts b/src/targeting.ts
index 49d72f7c023..082f5aa4c67 100644
--- a/src/targeting.ts
+++ b/src/targeting.ts
@@ -132,13 +132,12 @@ export function sortByDealAndPriceBucketOrCpm(useCpm = false) {
  * Return a map where each code in `adUnitCodes` maps to a list of GPT slots that match it.
  *
  * @param adUnitCodes
- * @param customSlotMatching
  * @param getSlots
  */
-export function getGPTSlotsForAdUnits(adUnitCodes: AdUnitCode[], customSlotMatching, getSlots = () => window.googletag.pubads().getSlots()): ByAdUnit<googletag.Slot[]> {
+export function getGPTSlotsForAdUnits(adUnitCodes: AdUnitCode[], getSlots = () => window.googletag.pubads().getSlots()): ByAdUnit<googletag.Slot[]> {
   return getSlots().reduce((auToSlots, slot) => {
-    const customMatch = isFn(customSlotMatching) && customSlotMatching(slot);
-    Object.keys(auToSlots).filter(isFn(customMatch) ? customMatch : isAdUnitCodeMatchingSlot(slot)).forEach(au => auToSlots[au].push(slot));
+    Object.keys(auToSlots).filter(isAdUnitCodeMatchingSlot(slot))
+      .forEach(au => auToSlots[au].push(slot));
     return auToSlots;
   }, Object.fromEntries(adUnitCodes.map(au => [au, []])));
 }
@@ -305,13 +304,13 @@ export function newTargeting(auctionManager) {
       return flatTargeting;
     },
 
-    setTargetingForGPT: hook('sync', function (adUnit?: AdUnitCode | AdUnitCode[], customSlotMatching?: SlotMatchingFn) {
+    setTargetingForGPT: hook('sync', function (adUnit?: AdUnitCode | AdUnitCode[]) {
       // get our ad unit codes
       const targetingSet: ByAdUnit<GPTTargetingValues> = targeting.getAllTargeting(adUnit);
 
       const resetMap = Object.fromEntries(pbTargetingKeys.map(key => [key, null]));
 
-      Object.entries(getGPTSlotsForAdUnits(Object.keys(targetingSet), customSlotMatching)).forEach(([targetId, slots]) => {
+      Object.entries(getGPTSlotsForAdUnits(Object.keys(targetingSet))).forEach(([targetId, slots]) => {
         slots.forEach(slot => {
           // now set new targeting keys
           Object.keys(targetingSet[targetId]).forEach(key => {
diff --git a/src/utils.js b/src/utils.js
index 973015336ba..7a39955c57c 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -798,7 +798,9 @@ export const compareCodeAndSlot = (slot, adUnitCode) => slot.getAdUnitPath() ===
  * @return filter function
  */
 export function isAdUnitCodeMatchingSlot(slot) {
-  return (adUnitCode) => compareCodeAndSlot(slot, adUnitCode);
+  const customGptSlotMatching = config.getConfig('customGptSlotMatching');
+  const match = isFn(customGptSlotMatching) && customGptSlotMatching(slot);
+  return isFn(match) ? match : (adUnitCode) => compareCodeAndSlot(slot, adUnitCode);
 }
 
 /**
diff --git a/src/utils/adUnits.ts b/src/utils/adUnits.ts
new file mode 100644
index 00000000000..4443a1a7906
--- /dev/null
+++ b/src/utils/adUnits.ts
@@ -0,0 +1,23 @@
+import type {AdUnitDefinition} from "../adUnits.ts";
+import type {BidRequest} from "../adapterManager.ts";
+import type {Bid} from "../bidfactory.ts";
+
+// TODO: for 11, this should be merged with the GPT/AST logic in secureCreatives
+// (after customGptSlotMatching becomes config - https://github.com/prebid/Prebid.js/issues/14408)
+export function getAdUnitElement(bidRequest: BidRequest<any>): HTMLElement
+export function getAdUnitElement(bidResponse: Bid): HTMLElement
+export function getAdUnitElement(adUnit: AdUnitDefinition): HTMLElement
+export function getAdUnitElement(target: {
+  code?: string,
+  adUnitCode?: string,
+  element?: HTMLElement
+}): HTMLElement {
+  if (target.element != null) {
+    return target.element;
+  }
+  const id = target.adUnitCode ?? target.code;
+  if (id) {
+    return document.getElementById(id);
+  }
+  return null;
+}
diff --git a/test/spec/modules/bidViewability_spec.js b/test/spec/modules/bidViewability_spec.js
index e33e4a9687b..04858f261e7 100644
--- a/test/spec/modules/bidViewability_spec.js
+++ b/test/spec/modules/bidViewability_spec.js
@@ -55,22 +55,6 @@ describe('#bidViewability', function() {
     pbjsWinningBid = Object.assign({}, PBJS_WINNING_BID);
   });
 
-  describe('isBidAdUnitCodeMatchingSlot', function() {
-    it('match found by GPT Slot getAdUnitPath', function() {
-      expect(bidViewability.isBidAdUnitCodeMatchingSlot(pbjsWinningBid, gptSlot)).to.equal(true);
-    });
-
-    it('match found by GPT Slot getSlotElementId', function() {
-      pbjsWinningBid.adUnitCode = 'DIV-1';
-      expect(bidViewability.isBidAdUnitCodeMatchingSlot(pbjsWinningBid, gptSlot)).to.equal(true);
-    });
-
-    it('match not found', function() {
-      pbjsWinningBid.adUnitCode = 'DIV-10';
-      expect(bidViewability.isBidAdUnitCodeMatchingSlot(pbjsWinningBid, gptSlot)).to.equal(false);
-    });
-  });
-
   describe('getMatchingWinningBidForGPTSlot', function() {
     let winningBidsArray;
     let sandbox
@@ -89,44 +73,40 @@ describe('#bidViewability', function() {
       sandbox.restore();
     })
 
-    it('should find a match by using customMatchFunction provided in config', function() {
-      // Needs config to be passed with customMatchFunction
-      const bidViewabilityConfig = {
-        customMatchFunction(bid, slot) {
-          return ('AD-' + slot.getAdUnitPath()) === bid.adUnitCode;
+    it('should find a match by using customGptSlotMatching provided in config', function() {
+      config.setConfig({
+        customGptSlotMatching: slot => {
+          return (adUnitCode) => ('AD-' + slot.getAdUnitPath()) === adUnitCode;
         }
-      };
+      });
       const newWinningBid = Object.assign({}, PBJS_WINNING_BID, {adUnitCode: 'AD-' + PBJS_WINNING_BID.adUnitCode});
       // Needs pbjs.getWinningBids to be implemented with match
       winningBidsArray.push(newWinningBid);
-      const wb = bidViewability.getMatchingWinningBidForGPTSlot(bidViewabilityConfig, gptSlot);
+      const wb = bidViewability.getMatchingWinningBidForGPTSlot(gptSlot);
       expect(wb).to.deep.equal(newWinningBid);
+      config.resetConfig();
     });
 
-    it('should NOT find a match by using customMatchFunction provided in config', function() {
-      // Needs config to be passed with customMatchFunction
-      const bidViewabilityConfig = {
-        customMatchFunction(bid, slot) {
-          return ('AD-' + slot.getAdUnitPath()) === bid.adUnitCode;
-        }
-      };
-      // Needs pbjs.getWinningBids to be implemented without match; winningBidsArray is set to empty in beforeEach
-      const wb = bidViewability.getMatchingWinningBidForGPTSlot(bidViewabilityConfig, gptSlot);
+    it('should NOT find a match when customGptSlotMatching is set and no winning bid matches', function() {
+      config.setConfig({
+        customGptSlotMatching: slot => (adUnitCode) => ('AD-' + slot.getAdUnitPath()) === adUnitCode
+      });
+      // winningBidsArray is empty in beforeEach, so no bid matches
+      const wb = bidViewability.getMatchingWinningBidForGPTSlot(gptSlot);
       expect(wb).to.equal(null);
+      config.resetConfig();
     });
 
     it('should find a match by using default matching function', function() {
-      // Needs config to be passed without customMatchFunction
-      // Needs pbjs.getWinningBids to be implemented with match
+      // No customGptSlotMatching in config; pbjs.getWinningBids returns matching bid
       winningBidsArray.push(PBJS_WINNING_BID);
-      const wb = bidViewability.getMatchingWinningBidForGPTSlot({}, gptSlot);
+      const wb = bidViewability.getMatchingWinningBidForGPTSlot(gptSlot);
       expect(wb).to.deep.equal(PBJS_WINNING_BID);
     });
 
     it('should NOT find a match by using default matching function', function() {
-      // Needs config to be passed without customMatchFunction
-      // Needs pbjs.getWinningBids to be implemented without match; winningBidsArray is set to empty in beforeEach
-      const wb = bidViewability.getMatchingWinningBidForGPTSlot({}, gptSlot);
+      // No customGptSlotMatching; winningBidsArray is empty in beforeEach
+      const wb = bidViewability.getMatchingWinningBidForGPTSlot(gptSlot);
       expect(wb).to.equal(null);
     });
   });
diff --git a/test/spec/modules/gptPreAuction_spec.js b/test/spec/modules/gptPreAuction_spec.js
index c369597ecbd..3ba49ede215 100644
--- a/test/spec/modules/gptPreAuction_spec.js
+++ b/test/spec/modules/gptPreAuction_spec.js
@@ -183,9 +183,8 @@ describe('GPT pre-auction module', () => {
 
     it('should use the customGptSlotMatching function if one is given', () => {
       config.setConfig({
-        gptPreAuction: {
-          customGptSlotMatching: slot =>
-            adUnitCode => adUnitCode.toUpperCase() === slot.getAdUnitPath().toUpperCase()
+        customGptSlotMatching: slot => {
+          return (adUnitCode) => adUnitCode.toUpperCase() === slot.getAdUnitPath().toUpperCase();
         }
       });
 
@@ -194,6 +193,7 @@ describe('GPT pre-auction module', () => {
       appendGptSlots([adUnit]);
       expect(adUnit.ortb2Imp.ext.data.adserver).to.be.an('object');
       expect(adUnit.ortb2Imp.ext.data.adserver).to.deep.equal({ name: 'gam', adslot: 'slotCode1' });
+      config.resetConfig();
     });
   });
 
@@ -208,27 +208,14 @@ describe('GPT pre-auction module', () => {
       expect(_currentConfig).to.be.an('object').that.is.empty;
     });
 
-    it('should accept custom functions in config', () => {
-      config.setConfig({
-        gptPreAuction: {
-          customGptSlotMatching: () => 'customGptSlot',
-        }
-      });
-
-      expect(_currentConfig.enabled).to.equal(true);
-      expect(_currentConfig.customGptSlotMatching).to.a('function');
-      expect(_currentConfig.customGptSlotMatching()).to.equal('customGptSlot');
-    });
-
     it('should check that custom functions in config are type function', () => {
       config.setConfig({
         gptPreAuction: {
-          customGptSlotMatching: 12345,
+          customPreAuction: 12345,
         }
       });
       expect(_currentConfig).to.deep.equal({
         enabled: true,
-        customGptSlotMatching: false,
         customPreAuction: false,
         useDefaultPreAuction: true
       });
diff --git a/test/spec/unit/core/targeting_spec.js b/test/spec/unit/core/targeting_spec.js
index 344229346c5..1f4d386a413 100644
--- a/test/spec/unit/core/targeting_spec.js
+++ b/test/spec/unit/core/targeting_spec.js
@@ -1641,22 +1641,22 @@ describe('targeting tests', function () {
 
     it('can find slots by ad unit path', () => {
       const paths = ['slot/1', 'slot/2']
-      expect(getGPTSlotsForAdUnits(paths, null, () => slots)).to.eql({[paths[0]]: [slots[0], slots[2]], [paths[1]]: [slots[1]]});
+      expect(getGPTSlotsForAdUnits(paths, () => slots)).to.eql({[paths[0]]: [slots[0], slots[2]], [paths[1]]: [slots[1]]});
     })
 
     it('can find slots by ad element ID', () => {
       const elementIds = ['div-1', 'div-2']
-      expect(getGPTSlotsForAdUnits(elementIds, null, () => slots)).to.eql({[elementIds[0]]: [slots[0]], [elementIds[1]]: [slots[1]]});
+      expect(getGPTSlotsForAdUnits(elementIds, () => slots)).to.eql({[elementIds[0]]: [slots[0]], [elementIds[1]]: [slots[1]]});
     })
 
     it('returns empty list on no match', () => {
-      expect(getGPTSlotsForAdUnits(['missing', 'slot/2'], null, () => slots)).to.eql({
+      expect(getGPTSlotsForAdUnits(['missing', 'slot/2'], () => slots)).to.eql({
         missing: [],
         'slot/2': [slots[1]]
       });
     });
 
-    it('can use customSlotMatching resolving to ad unit codes', () => {
+    it('can use customGptSlotMatching resolving to ad unit codes', () => {
       const csm = (slot) => {
         if (slot.getAdUnitPath() === 'slot/1') {
           return (au) => {
@@ -1664,13 +1664,17 @@ describe('targeting tests', function () {
           }
         }
       }
-      expect(getGPTSlotsForAdUnits(['div-2', 'custom'], csm, () => slots)).to.eql({
+      config.setConfig({
+        customGptSlotMatching: csm
+      })
+      expect(getGPTSlotsForAdUnits(['div-2', 'custom'], () => slots)).to.eql({
         'custom': [slots[0], slots[2]],
         'div-2': [slots[1]]
       })
+      config.resetConfig();
     });
 
-    it('can use customSlotMatching resolving to elementIds', () => {
+    it('can use customGptSlotMatching resolving to elementIds', () => {
       const csm = (slot) => {
         if (slot.getSlotElementId() === 'div-1') {
           return (au) => {
@@ -1678,14 +1682,18 @@ describe('targeting tests', function () {
           }
         }
       }
-      expect(getGPTSlotsForAdUnits(['div-2', 'custom'], csm, () => slots)).to.eql({
+      config.setConfig({
+        customGptSlotMatching: csm
+      })
+      expect(getGPTSlotsForAdUnits(['div-2', 'custom'], () => slots)).to.eql({
         'custom': [slots[0]],
         'div-2': [slots[1]]
       })
+      config.resetConfig();
     });
 
     it('can handle repeated adUnitCodes', () => {
-      expect(getGPTSlotsForAdUnits(['div-1', 'div-1'], null, () => slots)).to.eql({
+      expect(getGPTSlotsForAdUnits(['div-1', 'div-1'], () => slots)).to.eql({
         'div-1': [slots[0]]
       })
     })
diff --git a/test/spec/unit/pbjs_api_spec.js b/test/spec/unit/pbjs_api_spec.js
index 105b3392d00..5e58006f6f9 100644
--- a/test/spec/unit/pbjs_api_spec.js
+++ b/test/spec/unit/pbjs_api_spec.js
@@ -1068,11 +1068,18 @@ describe('Unit: Prebid Module', function () {
       });
     });
 
-    it('should set googletag targeting keys to specific slot with customSlotMatching', function () {
+    it('should set googletag targeting keys to specific slot with customGptSlotMatching', function () {
       // same ad unit code but two differnt divs
-      // we make sure we can set targeting for a specific one with customSlotMatching
+      // we make sure we can set targeting for a specific one with customGptSlotMatching
 
-      pbjs.setConfig({ enableSendAllBids: false });
+      pbjs.setConfig({
+        enableSendAllBids: false,
+        customGptSlotMatching: (slot) => {
+          return (adUnitCode) => {
+            return slots[0].getSlotElementId() === slot.getSlotElementId();
+          };
+        }
+      });
 
       var slots = createSlotArrayScenario2();
 
@@ -1080,11 +1087,7 @@ describe('Unit: Prebid Module', function () {
       slots[1].spySetTargeting.resetHistory();
       window.googletag.pubads().setSlots(slots);
       pbjs.setConfig({ targetingControls: {allBidsCustomTargeting: true }});
-      pbjs.setTargetingForGPTAsync([config.adUnitCodes[0]], (slot) => {
-        return (adUnitCode) => {
-          return slots[0].getSlotElementId() === slot.getSlotElementId();
-        };
-      });
+      pbjs.setTargetingForGPTAsync([config.adUnitCodes[0]]);
 
       var expected = getTargetingKeys();
       expect(slots[0].spySetTargeting.args).to.deep.contain.members(expected);