diff --git a/src/Symfony/Component/DependencyInjection/CHANGELOG.md b/src/Symfony/Component/DependencyInjection/CHANGELOG.md
index 8930b03ab6ff0..d3ae6c6c359c5 100644
--- a/src/Symfony/Component/DependencyInjection/CHANGELOG.md
+++ b/src/Symfony/Component/DependencyInjection/CHANGELOG.md
@@ -1,6 +1,11 @@
 CHANGELOG
 =========
 
+7.1
+---
+
+ * Add argument `$prepend` to `ContainerConfigurator::extension()` to prepend the configuration instead of appending it
+
 7.0
 ---
 
diff --git a/src/Symfony/Component/DependencyInjection/Loader/Configurator/ContainerConfigurator.php b/src/Symfony/Component/DependencyInjection/Loader/Configurator/ContainerConfigurator.php
index 883b5542ac51b..ad1110e17442a 100644
--- a/src/Symfony/Component/DependencyInjection/Loader/Configurator/ContainerConfigurator.php
+++ b/src/Symfony/Component/DependencyInjection/Loader/Configurator/ContainerConfigurator.php
@@ -48,8 +48,14 @@ public function __construct(ContainerBuilder $container, PhpFileLoader $loader,
         $this->env = $env;
     }
 
-    final public function extension(string $namespace, array $config): void
+    final public function extension(string $namespace, array $config, bool $prepend = false): void
     {
+        if ($prepend) {
+            $this->container->prependExtensionConfig($namespace, static::processValue($config));
+
+            return;
+        }
+
         if (!$this->container->hasExtension($namespace)) {
             $extensions = array_filter(array_map(fn (ExtensionInterface $ext) => $ext->getAlias(), $this->container->getExtensions()));
             throw new InvalidArgumentException(sprintf('There is no extension able to load the configuration for "%s" (in "%s"). Looked for namespace "%s", found "%s".', $namespace, $this->file, $namespace, $extensions ? implode('", "', $extensions) : 'none'));
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Extension/AbstractExtensionTest.php b/src/Symfony/Component/DependencyInjection/Tests/Extension/AbstractExtensionTest.php
index cb56983d365ce..9180ab8342da6 100644
--- a/src/Symfony/Component/DependencyInjection/Tests/Extension/AbstractExtensionTest.php
+++ b/src/Symfony/Component/DependencyInjection/Tests/Extension/AbstractExtensionTest.php
@@ -63,7 +63,7 @@ public function prependExtension(ContainerConfigurator $container, ContainerBuil
                 $container->extension('third', ['foo' => 'append']);
 
                 // prepend config
-                $builder->prependExtensionConfig('third', ['foo' => 'prepend']);
+                $container->extension('third', ['foo' => 'prepend'], true);
             }
         };
 
diff --git a/src/Symfony/Component/HttpKernel/Tests/Fixtures/AcmeFooBundle/AcmeFooBundle.php b/src/Symfony/Component/HttpKernel/Tests/Fixtures/AcmeFooBundle/AcmeFooBundle.php
index 4fba6260f9337..959536ecbdc51 100644
--- a/src/Symfony/Component/HttpKernel/Tests/Fixtures/AcmeFooBundle/AcmeFooBundle.php
+++ b/src/Symfony/Component/HttpKernel/Tests/Fixtures/AcmeFooBundle/AcmeFooBundle.php
@@ -31,7 +31,7 @@ public function configure(DefinitionConfigurator $definition): void
 
     public function prependExtension(ContainerConfigurator $container, ContainerBuilder $builder): void
     {
-        $container->extension('loaded', ['bar' => 'baz']);
+        $container->extension('loaded', ['bar' => 'baz'], true);
     }
 
     public function loadExtension(array $config, ContainerConfigurator $container, ContainerBuilder $builder): void