diff --git a/modules/33acrossBidAdapter.js b/modules/33acrossBidAdapter.js
index 1cf885ed6e4..801a5d564a3 100644
--- a/modules/33acrossBidAdapter.js
+++ b/modules/33acrossBidAdapter.js
@@ -1,8 +1,7 @@
+import { registerBidder } from '../src/adapters/bidderFactory';
+import { config } from '../src/config';
 import * as utils from '../src/utils';
 
-const { registerBidder } = require('../src/adapters/bidderFactory');
-const { config } = require('../src/config');
-
 const BIDDER_CODE = '33across';
 const END_POINT = 'https://ssc.33across.com/api/v1/hb';
 const SYNC_ENDPOINT = 'https://de.tynt.com/deb/v2?m=xch&rt=html';
@@ -32,17 +31,43 @@ function _isViewabilityMeasurable(element) {
 }
 
 function _getViewability(element, topWin, { w, h } = {}) {
-  return utils.getWindowTop().document.visibilityState === 'visible'
+  return topWin.document.visibilityState === 'visible'
     ? _getPercentInView(element, topWin, { w, h })
     : 0;
 }
 
+function _mapAdUnitPathToElementId(adUnitCode) {
+  if (utils.isGptPubadsDefined()) {
+    const adSlots = googletag.pubads().getSlots();
+    const isMatchingAdSlot = utils.isSlotMatchingAdUnitCode(adUnitCode);
+
+    for (let i = 0; i < adSlots.length; i++) {
+      if (isMatchingAdSlot(adSlots[i])) {
+        const id = adSlots[i].getSlotElementId();
+
+        utils.logInfo(`[33Across Adapter] Map ad unit path to HTML element id: '${adUnitCode}' -> ${id}`);
+
+        return id;
+      }
+    }
+  }
+
+  utils.logWarn(`[33Across Adapter] Unable to locate element for ad unit code: '${adUnitCode}'`);
+
+  return null;
+}
+
+function _getAdSlotHTMLElement(adUnitCode) {
+  return document.getElementById(adUnitCode) ||
+    document.getElementById(_mapAdUnitPathToElementId(adUnitCode));
+}
+
 // Infer the necessary data from valid bid for a minimal ttxRequest and create HTTP request
 // NOTE: At this point, TTX only accepts request for a single impression
 function _createServerRequest(bidRequest, gdprConsent) {
   const ttxRequest = {};
   const params = bidRequest.params;
-  const element = document.getElementById(bidRequest.adUnitCode);
+  const element = _getAdSlotHTMLElement(bidRequest.adUnitCode);
   const sizes = _transformSizes(bidRequest.sizes);
   const minSize = _getMinSize(sizes);
 
@@ -52,10 +77,6 @@ function _createServerRequest(bidRequest, gdprConsent) {
 
   const contributeViewability = ViewabilityContributor(viewabilityAmount);
 
-  if (element === null) {
-    utils.logWarn(`Unable to locate element with id: '${bidRequest.adUnitCode}'`);
-  }
-
   /*
    * Infer data for the request payload
    */
@@ -264,13 +285,14 @@ function isBidRequestValid(bid) {
 // - the server, at this point, also doesn't need the consent string to handle gdpr compliance. So passing
 //    value whether set or not, for the sake of future dev.
 function buildRequests(bidRequests, bidderRequest) {
-  const gdprConsent = Object.assign({ consentString: undefined, gdprApplies: false }, bidderRequest && bidderRequest.gdprConsent);
+  const gdprConsent = Object.assign({
+    consentString: undefined,
+    gdprApplies: false
+  }, bidderRequest && bidderRequest.gdprConsent);
 
   adapterState.uniqueSiteIds = bidRequests.map(req => req.params.siteId).filter(utils.uniques);
 
-  return bidRequests.map((req) => {
-    return _createServerRequest(req, gdprConsent);
-  });
+  return bidRequests.map(req => _createServerRequest(req, gdprConsent));
 }
 
 // NOTE: At this point, the response from 33exchange will only ever contain one bid i.e. the highest bid
diff --git a/modules/33acrossBidAdapter.md b/modules/33acrossBidAdapter.md
index bdb2b944861..58e3b2b273a 100644
--- a/modules/33acrossBidAdapter.md
+++ b/modules/33acrossBidAdapter.md
@@ -16,7 +16,7 @@ Connects to 33Across's exchange for bids.
 ```
 var adUnits = [
 {
-    code: '33across-hb-ad-123456-1',    
+    code: '33across-hb-ad-123456-1', // ad slot HTML element ID   
     sizes: [
         [300, 250], 
         [728, 90]
diff --git a/test/spec/modules/33acrossBidAdapter_spec.js b/test/spec/modules/33acrossBidAdapter_spec.js
index 1fc77a7e14d..7e1a8619c63 100644
--- a/test/spec/modules/33acrossBidAdapter_spec.js
+++ b/test/spec/modules/33acrossBidAdapter_spec.js
@@ -337,8 +337,8 @@ describe('33acrossBidAdapter:', function () {
 
         utils.getWindowTop.restore();
         utils.getWindowSelf.restore();
-        sandbox.stub(utils, 'getWindowTop').returns(win);
-        sandbox.stub(utils, 'getWindowSelf').returns({});
+        sandbox.stub(utils, 'getWindowTop').returns({});
+        sandbox.stub(utils, 'getWindowSelf').returns(win);
 
         expect(spec.buildRequests(bidRequests)).to.deep.equal([ serverRequest ]);
       });