diff --git a/src/websocket.js b/src/websocket.js
index 5a9252aa..ecb3d2f3 100644
--- a/src/websocket.js
+++ b/src/websocket.js
@@ -51,6 +51,9 @@ class WebSocket extends EventTarget {
      * registered :-)
      */
     delay(function delayCallback() {
+      if (this.readyState !== WebSocket.CONNECTING) {
+        return;
+      }
       if (server) {
         if (
           server.options.verifyClient &&
diff --git a/tests/functional/close-algorithm.test.js b/tests/functional/close-algorithm.test.js
index 2f840b46..62221849 100644
--- a/tests/functional/close-algorithm.test.js
+++ b/tests/functional/close-algorithm.test.js
@@ -88,6 +88,10 @@ test.cb('that if the readyState is CONNECTING we fail the connection and close',
 
   mockSocket.readyState = WebSocket.CONNECTING;
 
+  mockSocket.onopen = () => {
+    t.fail('open should not have been called');
+  };
+
   mockSocket.onerror = () => {
     t.is(mockSocket.readyState, WebSocket.CLOSED);
   };