diff --git a/lib/runner.js b/lib/runner.js
index f19a4060eb..8831c8e1cb 100644
--- a/lib/runner.js
+++ b/lib/runner.js
@@ -892,7 +892,7 @@ function hasOnly(suite) {
 function filterLeaks(ok, globals) {
   return filter(globals, function(key) {
     // Firefox and Chrome exposes iframes as index inside the window object
-    if (/^d+/.test(key)) {
+    if (/^\d+/.test(key)) {
       return false;
     }
 
diff --git a/test/runner.js b/test/runner.js
index 37aeb22d6f..6168bb3e34 100644
--- a/test/runner.js
+++ b/test/runner.js
@@ -179,6 +179,15 @@ describe('Runner', function(){
       });
       runner.checkGlobals(test);
     })
+
+    it('should emit "fail" when a global beginning with d is introduced', function(done) {
+      global.derp = 'bar';
+      runner.on('fail', function(test, err){
+        delete global.derp;
+        done();
+      });
+      runner.checkGlobals('im a test');
+    });
   })
 
   describe('.hook(name, fn)', function(){