diff --git a/Firestore/src/DocumentReference.php b/Firestore/src/DocumentReference.php
index 843e73916ee..79e824d3df6 100644
--- a/Firestore/src/DocumentReference.php
+++ b/Firestore/src/DocumentReference.php
@@ -418,7 +418,7 @@ function ($collectionId) {
      */
     protected function batchFactory()
     {
-        if (!class_exists(WriteBatch::class)) {
+        if (!class_exists(WriteBatch::class, false)) {
             class_alias(BulkWriter::class, WriteBatch::class);
         }
         return new BulkWriter(
diff --git a/Firestore/src/FirestoreClient.php b/Firestore/src/FirestoreClient.php
index 39db0de53ed..23e93c09539 100644
--- a/Firestore/src/FirestoreClient.php
+++ b/Firestore/src/FirestoreClient.php
@@ -178,7 +178,7 @@ public function __construct(array $config = [])
      */
     public function batch()
     {
-        if (!class_exists(WriteBatch::class)) {
+        if (!class_exists(WriteBatch::class, false)) {
             class_alias(BulkWriter::class, WriteBatch::class);
         }
         return new BulkWriter(