diff --git a/pkg/master/master.go b/pkg/master/master.go
index a04ca42750d..5367e4d2530 100644
--- a/pkg/master/master.go
+++ b/pkg/master/master.go
@@ -672,7 +672,7 @@ func (m *Master) init(c *Config) {
 			Versions:         expAPIVersions,
 			PreferredVersion: unversioned.GroupVersion{GroupVersion: storageVersion, Version: apiutil.GetVersion(storageVersion)},
 		}
-		apiserver.AddGroupWebService(m.handlerContainer, c.APIGroupPrefix+"/"+latest.GroupOrDie("extensions").Group+"/", group)
+		apiserver.AddGroupWebService(m.handlerContainer, c.APIGroupPrefix+"/"+latest.GroupOrDie("extensions").Group, group)
 		allGroups = append(allGroups, group)
 		apiserver.InstallServiceErrorHandler(m.handlerContainer, m.newRequestInfoResolver(), []string{expVersion.Version})
 	}