diff --git a/django/contrib/admin/views/main.py b/django/contrib/admin/views/main.py
index fd2849ba5e..9c2927000a 100644
--- a/django/contrib/admin/views/main.py
+++ b/django/contrib/admin/views/main.py
@@ -79,13 +79,6 @@ def change_list(request, app_label, module_name):
 
     lookup_mod, lookup_opts = mod, opts
 
-    if opts.one_to_one_field:
-        lookup_mod = opts.one_to_one_field.rel.to.get_model_module()
-        lookup_opts = lookup_mod.Klass._meta
-        # If lookup_opts doesn't have admin set, give it the default meta.Admin().
-        if not lookup_opts.admin:
-            lookup_opts.admin = meta.Admin()
-
     # Get search parameters from the query string.
     try:
         page_num = int(request.GET.get(PAGE_VAR, 0))
diff --git a/django/core/meta/fields.py b/django/core/meta/fields.py
index bf836c8390..27ce0670d5 100644
--- a/django/core/meta/fields.py
+++ b/django/core/meta/fields.py
@@ -48,11 +48,11 @@ def manipulator_valid_rel_key(f, self, field_data, all_data):
 def manipulator_validator_unique(f, opts, self, field_data, all_data):
     "Validates that the value is unique for this field."
     if f.rel and isinstance(f.rel, ManyToOne):
-        lookup_type = 'pk'
+        lookup_type = '%s__%s__exact' % (f.name, f.rel.get_related_field().name)
     else:
-        lookup_type = 'exact'
+        lookup_type = '%s__exact' % (f.name, lookup_type)
     try:
-        old_obj = opts.get_model_module().get_object(**{'%s__%s' % (f.name, lookup_type): field_data})
+        old_obj = opts.get_model_module().get_object(**{lookup_type: field_data})
     except ObjectDoesNotExist:
         return
     if hasattr(self, 'original_object') and getattr(self.original_object, opts.pk.attname) == getattr(old_obj, opts.pk.attname):