diff --git a/src/index.js b/src/index.js
index 9fe46370..bb5251e0 100644
--- a/src/index.js
+++ b/src/index.js
@@ -570,6 +570,10 @@ function sendPartialResponse(
     '',
   ].join('\r\n');
   response.write(data);
+  if (typeof response.flush === 'function') {
+    // flush response if compression middleware is used
+    response.flush();
+  }
 }
 
 /**