diff --git a/lib/Doctrine/ORM/UnitOfWork.php b/lib/Doctrine/ORM/UnitOfWork.php
index 8efeb9e8f..7044ce57e 100644
--- a/lib/Doctrine/ORM/UnitOfWork.php
+++ b/lib/Doctrine/ORM/UnitOfWork.php
@@ -3477,7 +3477,8 @@ class UnitOfWork implements PropertyChangedListener
     private function clearEntityInsertionsForEntityName($entityName)
     {
         foreach ($this->entityInsertions as $hash => $entity) {
-            if (get_class($entity) === $entityName) {
+            // note: performance optimization - `instanceof` is much faster than a function call
+            if ($entity instanceof $entityName && get_class($entity) === $entityName) {
                 unset($this->entityInsertions[$hash]);
             }
         }