diff --git a/lib/rabl/engine.rb b/lib/rabl/engine.rb
index ef01fbaa..aa86b1b1 100644
--- a/lib/rabl/engine.rb
+++ b/lib/rabl/engine.rb
@@ -56,7 +56,8 @@ def object(data)
     # Sets the object as a collection casted to a simple array
     # collection @users
     def collection(data)
-      object(data.to_a)
+      data = data.respond_to?(:each_pair) ? data.keys.first : data
+      self.object(data)
     end
 
     # Indicates an attribute or method should be included in the json output