diff --git a/src/Symfony/Bridge/PhpUnit/Legacy/SymfonyTestsListenerTrait.php b/src/Symfony/Bridge/PhpUnit/Legacy/SymfonyTestsListenerTrait.php
index 69bbcfc09eab..290c53cfee9d 100644
--- a/src/Symfony/Bridge/PhpUnit/Legacy/SymfonyTestsListenerTrait.php
+++ b/src/Symfony/Bridge/PhpUnit/Legacy/SymfonyTestsListenerTrait.php
@@ -47,8 +47,13 @@ public function __construct(array $mockedNamespaces = array())
     {
         if (class_exists('PHPUnit_Util_Blacklist')) {
             \PHPUnit_Util_Blacklist::$blacklistedClassNames['\Symfony\Bridge\PhpUnit\Legacy\SymfonyTestsListenerTrait'] = 2;
-        } else {
-            Blacklist::$blacklistedClassNames['\Symfony\Bridge\PhpUnit\Legacy\SymfonyTestsListenerTrait'] = 2;
+        } elseif (class_exists(Blacklist::class)) {
+            $className = '\Symfony\Bridge\PhpUnit\Legacy\SymfonyTestsListenerTrait';
+            if (method_exists(Blacklist::class, 'addDirectory')) {
+                Blacklist::addDirectory($className);
+            } else {
+                Blacklist::$blacklistedClassNames[$className] = 2;
+            }
         }
 
         $warn = false;
diff --git a/src/Symfony/Bridge/PhpUnit/bin/simple-phpunit b/src/Symfony/Bridge/PhpUnit/bin/simple-phpunit
index d2c23f2025b7..90d6ac51834e 100755
--- a/src/Symfony/Bridge/PhpUnit/bin/simple-phpunit
+++ b/src/Symfony/Bridge/PhpUnit/bin/simple-phpunit
@@ -126,9 +126,14 @@ if (!class_exists('SymfonyBlacklistPhpunit', false)) {
 if (class_exists('PHPUnit_Util_Blacklist')) {
     PHPUnit_Util_Blacklist::$blacklistedClassNames['SymfonyBlacklistPhpunit'] = 1;
     PHPUnit_Util_Blacklist::$blacklistedClassNames['SymfonyBlacklistSimplePhpunit'] = 1;
-} else {
-    PHPUnit\Util\Blacklist::$blacklistedClassNames['SymfonyBlacklistPhpunit'] = 1;
-    PHPUnit\Util\Blacklist::$blacklistedClassNames['SymfonyBlacklistSimplePhpunit'] = 1;
+} elseif (class_exists(\PHPUnit\Util\Blacklist::class)) {
+    if (method_exists(\PHPUnit\Util\Blacklist::class, 'addDirectory')) {
+        \PHPUnit\Util\Blacklist::addDirectory('SymfonyBlacklistPhpunit');
+        \PHPUnit\Util\Blacklist::addDirectory('SymfonyBlacklistSimplePhpunit');
+    } else {
+        \PHPUnit\Util\Blacklist::$blacklistedClassNames['SymfonyBlacklistPhpunit'] = 1;
+        \PHPUnit\Util\Blacklist::$blacklistedClassNames['SymfonyBlacklistSimplePhpunit'] = 1;
+    }
 }
 
 Symfony\Bridge\PhpUnit\TextUI\Command::main();
diff --git a/src/Symfony/Bridge/PhpUnit/composer.json b/src/Symfony/Bridge/PhpUnit/composer.json
index f7d9492613ab..30b3cc23f63d 100644
--- a/src/Symfony/Bridge/PhpUnit/composer.json
+++ b/src/Symfony/Bridge/PhpUnit/composer.json
@@ -24,7 +24,7 @@
         "symfony/debug": "For tracking deprecated interfaces usages at runtime with DebugClassLoader"
     },
     "conflict": {
-        "phpunit/phpunit": "<4.8.35|<5.4.3,>=5.0|<6.4,>=6.0"
+        "phpunit/phpunit": "<4.8.35|<5.4.3,>=5.0|<6.4,>=6.0|9.1.2"
     },
     "autoload": {
         "files": [ "bootstrap.php" ],