diff --git a/core/modules/system/tests/src/FunctionalJavascript/OffCanvasTestBase.php b/core/modules/system/tests/src/FunctionalJavascript/OffCanvasTestBase.php
index d3f446cf6a..525e61b508 100644
--- a/core/modules/system/tests/src/FunctionalJavascript/OffCanvasTestBase.php
+++ b/core/modules/system/tests/src/FunctionalJavascript/OffCanvasTestBase.php
@@ -62,11 +62,7 @@ protected function enableTheme($theme) {
    * Waits for off-canvas dialog to open.
    */
   protected function waitForOffCanvasToOpen() {
-    $web_assert = $this->assertSession();
-    // Wait just slightly longer than the off-canvas dialog CSS animation.
-    // @see core/misc/dialog/off-canvas.motion.css
-    $this->getSession()->wait(800);
-    $web_assert->assertWaitOnAjaxRequest();
+    $this->assertSession()->waitForId('#drupal-off-canvas');
     $this->assertElementVisibleAfterWait('css', '#drupal-off-canvas');
   }