diff --git a/doc/config.rst b/doc/config.rst
index 69ac7ced67..69063ba814 100644
--- a/doc/config.rst
+++ b/doc/config.rst
@@ -1389,7 +1389,7 @@ Server connection settings
 
     .. note::
 
-        Enabling this option might give you big performance boost on older
+        Enabling this option might give you a big performance boost on older
         MySQL servers.
 
 .. config:option:: $cfg['Servers'][$i]['SignonScript']