Marcus Rashford furiously booted a dressing room door at Turf Moor after being sent off in Manchester Uniteds 2-0 win against Burnley, reports claim.
The England international saw red for a headbutt having been on the pitch for just eight minutes as a second half substitute.
Rashford retaliated after former United defender Phil Bardsley kicked out at him and Mourinho labelled him as naive for being drawn into an altercation.
The 20-year-old was furious at himself for getting himself tangled up with the Burnley full-back and he took out his frustration on a door in the dressing room, according to the Daily Mail.
While no damage was done, it offers an insight to the pressure the youngster is feeling as he looks to establish himself under Mourinho.
The attacker has struggled to hold down a starting berth at Old Trafford and his quickfire red after replacing Alexis Sanchez wont have done his cause any good.
I dont know what happened. I would say it was naive, Mourinho said after the win.
It was a kid and a very experienced man. Bardsleys been in the game for 20 years and Marcus is a naive boy.
Rashford was quick to apologise to his manager and the clubs supporters after the match, taking to Twitter to vent his frustration at his behaviour.
Emotions got the better of me, I shouldnt of [sic] reacted like that, he wrote.
Sorry to everyone at the club and all the fans.
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