diff --git a/index.js b/index.js
index 4451fdb..5f0318a 100644
--- a/index.js
+++ b/index.js
@@ -103,6 +103,7 @@ function mock(superagent) {
           cb && cb(ex, null);
         }
       }, value(mock.timeout), state.request);
+      return this;
     } else {
       oldEnd.call(this, cb);
     }