To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video
That's the claim from William Gallas, who played under both managers during spells at Arsenal and Chelsea.
Wenger has failed to win the Premier League with Arsenal since 2004, while Mourinho has claimed seven league titles across Europe during that same period.
The Frenchman has been branded a 'specialist in failure' by his managerial rival – now in charge of Manchester United - and is under intense pressure from Gunners fans with another title-less campaign looking likely.