diff --git a/src/Symfony/Component/DependencyInjection/Container.php b/src/Symfony/Component/DependencyInjection/Container.php
index 88e1f26ecde07..0e6a6c7976df4 100644
--- a/src/Symfony/Component/DependencyInjection/Container.php
+++ b/src/Symfony/Component/DependencyInjection/Container.php
@@ -238,7 +238,7 @@ public function get($id, $invalidBehavior = self::EXCEPTION_ON_INVALID_REFERENCE
     {
         $id = strtolower($id);
 
-        if (isset($this->services[$id])) {
+        if (array_key_exists($id, $this->services)) {
             return $this->services[$id];
         }