diff --git a/graphene_django_optimizer/query.py b/graphene_django_optimizer/query.py
index 78652a730cd51243173810c7111bae1941f799f5..070089cb8c8a5aca2e8be8e8feaf1b6a1fa02949 100644
--- a/graphene_django_optimizer/query.py
+++ b/graphene_django_optimizer/query.py
@@ -51,7 +51,7 @@ class QueryOptimizer(object):
 
     def optimize(self, queryset):
         info = self.root_info
-        field_def = get_field_def(info.schema, info.parent_type, info.field_name)
+        field_def = get_field_def(info.schema, info.parent_type, info.field_nodes[0])
         store = self._optimize_gql_selections(
             self._get_type(field_def),
             info.field_nodes[0],