diff --git a/stream-testkit/src/main/scala/org/apache/pekko/stream/testkit/StreamTestKit.scala b/stream-testkit/src/main/scala/org/apache/pekko/stream/testkit/StreamTestKit.scala
index a8525b03ba..9486e0d11a 100644
--- a/stream-testkit/src/main/scala/org/apache/pekko/stream/testkit/StreamTestKit.scala
+++ b/stream-testkit/src/main/scala/org/apache/pekko/stream/testkit/StreamTestKit.scala
@@ -852,10 +852,10 @@ object TestSubscriber {
      * @param max wait no more than max time, otherwise throw AssertionError
      */
     def expectNextWithTimeoutPF[T](max: Duration, f: PartialFunction[Any, T]): T = {
-      val pf: PartialFunction[SubscriberEvent, Any] = {
-        case OnNext(n) => n
+      val pf: PartialFunction[SubscriberEvent, T] = {
+        case OnNext(n) if f.isDefinedAt(n) => f(n)
       }
-      expectEventWithTimeoutPF(max, pf.andThen(f))
+      expectEventWithTimeoutPF[T](max, pf)
     }
 
     /**