diff --git a/resources/core.py b/resources/core.py
index e45c5b8..c75d73b 100644
--- a/resources/core.py
+++ b/resources/core.py
@@ -190,8 +190,8 @@ class Interface(object):
         else:
             # Assume decorator usage.
 
-            def decorator(f):
-                self.map(key, f)
+            def decorator(r):
+                self.map(key, resource=r, collection=collection)
                 return f
 
             return decorator