diff --git a/unittest/cycletimer.h b/unittest/cycletimer.h
index c5f5568ce2..e1a1371952 100644
--- a/unittest/cycletimer.h
+++ b/unittest/cycletimer.h
@@ -25,6 +25,7 @@ class CycleTimer {
   void Reset() {
     running_ = false;
     sum_ = 0;
+    start_ = 0;
   }
 
   // When Start() is called multiple times, only the most recent is used.