diff --git a/dddp/api.py b/dddp/api.py
index b60a066..2681bc8 100644
--- a/dddp/api.py
+++ b/dddp/api.py
@@ -285,7 +285,7 @@ class Collection(APIMixin):
                 name, rel = (user_rel.split('__', 1) + [None])[:2]
                 field = meta.pk if name == 'pk' else meta.get_field(name)
                 # generate `filter_obj` (instance of django.db.models.Q)
-                if field not in meta.local_fields:
+                if field.related_model is not None:
                     # user_rel spans a join - ensure efficient SQL is generated
                     # such as `...WHERE foo_id IN (SELECT foo.id FROM ...)`
                     # rather than creating an explosion of INNER JOINS.