diff --git a/tools/run_tests/run_xds_tests.py b/tools/run_tests/run_xds_tests.py
index 1b5ffb34d0a..f8146294ecd 100755
--- a/tools/run_tests/run_xds_tests.py
+++ b/tools/run_tests/run_xds_tests.py
@@ -1090,8 +1090,6 @@ def patch_url_map_backend_service(gcp,
     } if services_with_weights else None
 
     config = {
-        'defaultService':
-            backend_service.url,
         'pathMatchers': [{
             'name': _PATH_MATCHER_NAME,
             'defaultService': default_service,