diff --git a/src/Symfony/Component/HttpKernel/DataCollector/DumpDataCollector.php b/src/Symfony/Component/HttpKernel/DataCollector/DumpDataCollector.php
index f9730b148504..d0ca671e056b 100644
--- a/src/Symfony/Component/HttpKernel/DataCollector/DumpDataCollector.php
+++ b/src/Symfony/Component/HttpKernel/DataCollector/DumpDataCollector.php
@@ -166,7 +166,9 @@ public function collect(Request $request, Response $response, \Exception $except
 
     public function reset()
     {
-        $this->stopwatch->reset();
+        if ($this->stopwatch) {
+            $this->stopwatch->reset();
+        }
         $this->data = array();
         $this->dataCount = 0;
         $this->isCollected = false;