diff --git a/testing/web-platform/tests/navigation-api/focus-reset/basic.html b/testing/web-platform/tests/navigation-api/focus-reset/basic.html
index 8a62d88ba6598..1ffaa022ee4ba 100644
--- a/testing/web-platform/tests/navigation-api/focus-reset/basic.html
+++ b/testing/web-platform/tests/navigation-api/focus-reset/basic.html
@@ -1,6 +1,8 @@
 <!doctype html>
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
 
 <script type="module">
 import { testFocusWasReset, testFocusWasNotReset } from "./resources/helpers.mjs";
diff --git a/testing/web-platform/tests/navigation-api/focus-reset/multiple-transitionWhile.html b/testing/web-platform/tests/navigation-api/focus-reset/multiple-transitionWhile.html
index c1d028524a5e8..3420991f9a861 100644
--- a/testing/web-platform/tests/navigation-api/focus-reset/multiple-transitionWhile.html
+++ b/testing/web-platform/tests/navigation-api/focus-reset/multiple-transitionWhile.html
@@ -1,6 +1,8 @@
 <!doctype html>
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
 
 <script type="module">
 import { testFocusWasReset, testFocusWasNotReset } from "./resources/helpers.mjs";
diff --git a/testing/web-platform/tests/navigation-api/focus-reset/resources/helpers.mjs b/testing/web-platform/tests/navigation-api/focus-reset/resources/helpers.mjs
index e7e9a52009dd4..0a8a0439e1c88 100644
--- a/testing/web-platform/tests/navigation-api/focus-reset/resources/helpers.mjs
+++ b/testing/web-platform/tests/navigation-api/focus-reset/resources/helpers.mjs
@@ -2,12 +2,19 @@
 // clean up any navigate event listeners, e.g. by using { once: true }, between
 // tests.
 
+const TAB_KEY = "\uE004";
+
 export function testFocusWasReset(setupFunc, description) {
   promise_test(async t => {
     setupFunc(t);
 
     const button = document.body.appendChild(document.createElement("button"));
-    t.add_cleanup(() => { button.remove(); });
+    const button2 = document.body.appendChild(document.createElement("button"));
+    button2.tabIndex = 0;
+    t.add_cleanup(() => {
+      button.remove();
+      button2.remove();
+    });
 
     assert_equals(document.activeElement, document.body, "Start on body");
     button.focus();
@@ -20,6 +27,11 @@ export function testFocusWasReset(setupFunc, description) {
 
     await finished.catch(() => {});
     assert_equals(document.activeElement, document.body, "Focus reset after the transition");
+
+    button2.onfocus = t.unreached_func("button2 must not be focused after pressing Tab");
+    const focusPromise = waitForFocus(t, button);
+    await test_driver.send_keys(document.body, TAB_KEY);
+    await focusPromise;
   }, description);
 }
 
@@ -28,7 +40,12 @@ export function testFocusWasNotReset(setupFunc, description) {
     setupFunc(t);
 
     const button = document.body.appendChild(document.createElement("button"));
-    t.add_cleanup(() => { button.remove(); });
+    const button2 = document.body.appendChild(document.createElement("button"));
+    button2.tabIndex = 0;
+    t.add_cleanup(() => {
+      button.remove();
+      button2.remove();
+    });
 
     assert_equals(document.activeElement, document.body, "Start on body");
     button.focus();
@@ -41,5 +58,16 @@ export function testFocusWasNotReset(setupFunc, description) {
 
     await finished.catch(() => {});
     assert_equals(document.activeElement, button, "Focus stays on the button after the transition");
+
+    button.onfocus = t.unreached_func("button must not be focused after pressing Tab");
+    const focusPromise = waitForFocus(t, button2);
+    await test_driver.send_keys(document.body, TAB_KEY);
+    await focusPromise;
   }, description);
 }
+
+function waitForFocus(t, target) {
+  return new Promise(resolve => {
+    target.addEventListener("focus", () => resolve(), { once: true });
+  });
+}
