diff --git a/components/script/dom/performance.rs b/components/script/dom/performance.rs
index 8e85543f8e32..7cef2f280100 100644
--- a/components/script/dom/performance.rs
+++ b/components/script/dom/performance.rs
@@ -182,6 +182,15 @@ impl Performance {
             Some(p) => p,
             None => return,
         };
+
+        if self.pending_notification_observers_task.get() {
+            if let Some(o) = observers.iter().nth(index) {
+                DOMPerformanceObserver::new(&self.global(),
+                                            o.observer.callback(),
+                                            o.observer.entries()).notify();
+            }
+        }
+
         observers.remove(index);
     }
 
diff --git a/tests/wpt/metadata/performance-timeline/po-disconnect.any.js.ini b/tests/wpt/metadata/performance-timeline/po-disconnect.any.js.ini
deleted file mode 100644
index 53a4c5c6b3e7..000000000000
--- a/tests/wpt/metadata/performance-timeline/po-disconnect.any.js.ini
+++ /dev/null
@@ -1,13 +0,0 @@
-[po-disconnect.any.html]
-  type: testharness
-  expected: TIMEOUT
-  [An observer disconnected after a mark must receive the mark]
-    expected: TIMEOUT
-
-
-[po-disconnect.any.worker.html]
-  type: testharness
-  expected: TIMEOUT
-  [An observer disconnected after a mark must receive the mark]
-    expected: TIMEOUT
-