diff --git a/rest_framework/validators.py b/rest_framework/validators.py
index a21f67e60..83ad6f7d8 100644
--- a/rest_framework/validators.py
+++ b/rest_framework/validators.py
@@ -35,7 +35,7 @@ class UniqueValidator(object):
         """
         # Determine the underlying model field name. This may not be the
         # same as the serializer field name if `source=<>` is set.
-        self.field_name = serializer_field.source_attrs[0]
+        self.field_name = serializer_field.source_attrs[-1]
         # Determine the existing instance, if this is an update operation.
         self.instance = getattr(serializer_field.parent, 'instance', None)
 
@@ -174,8 +174,8 @@ class BaseUniqueForValidator(object):
         """
         # Determine the underlying model field names. These may not be the
         # same as the serializer field names if `source=<>` is set.
-        self.field_name = serializer.fields[self.field].source_attrs[0]
-        self.date_field_name = serializer.fields[self.date_field].source_attrs[0]
+        self.field_name = serializer.fields[self.field].source_attrs[-1]
+        self.date_field_name = serializer.fields[self.date_field].source_attrs[-1]
         # Determine the existing instance, if this is an update operation.
         self.instance = getattr(serializer, 'instance', None)