Substitute Wissam Ben Yedder struck twice to earn the 2-1 win. Romelu Lukaku lashed home from close range with seven minutes remaining, but it proved to be merely a consolation.
Afterwards, Mourinho said at the final whistle: "It's a disappointment but it's football, when a team wins, we all win and when a team loses, the coach loses.
"I lost today, I probably made mistakes.
"It would have been more fair to draw with goals."