diff --git a/core/scripts/pptr-run-devtools.js b/core/scripts/pptr-run-devtools.js
index 1b383ca5aa92..8259cc3f5913 100644
--- a/core/scripts/pptr-run-devtools.js
+++ b/core/scripts/pptr-run-devtools.js
@@ -296,6 +296,7 @@ async function testUrlFromDevtools(url, options = {}) {
     executablePath: getChromePath(),
     args: chromeFlags,
     devtools: true,
+    defaultViewport: null,
   });
 
   try {