diff --git a/src/Asset/CriticalCssCollectionRenderer.php b/src/Asset/CriticalCssCollectionRenderer.php
index 439e3d8..592eca8 100644
--- a/src/Asset/CriticalCssCollectionRenderer.php
+++ b/src/Asset/CriticalCssCollectionRenderer.php
@@ -144,7 +144,7 @@ class CriticalCssCollectionRenderer implements AssetCollectionRendererInterface
   public function render(array $assets) {
     $elements = [];
 
-    if ($this->config->get('enabled') === TRUE) {
+    if ($this->config->get('enabled') === TRUE && !\Drupal::request()->isXmlHttpRequest()) {
       $enabled_themes = $this->config->get('enabled_themes');
       $active_theme = $this->themeManager->getActiveTheme()->getName();
       if (empty($enabled_themes) || in_array($active_theme, $enabled_themes, TRUE)) {