diff --git a/index.js b/index.js
index 4c72fe2..42ce0da 100644
--- a/index.js
+++ b/index.js
@@ -2,10 +2,10 @@
  * Expose `requestAnimationFrame()`.
  */
 
-exports = module.exports = window.requestAnimationFrame
+exports = module.exports = (window.requestAnimationFrame
   || window.webkitRequestAnimationFrame
   || window.mozRequestAnimationFrame
-  || fallback;
+  || fallback).bind(window);
 
 /**
  * Fallback implementation.