Alexis Sanchez was involved in a heated training ground row with Manchester United academy graduate Mason Greenwood, with angry words reportedly exchanged between the pair.
The former Arsenal man is desperately trying to build up his fitness after returning from the Copa America with a hamstring injury that he picked up in the third place play-off.
In one of his first training sessions back at the club following his injury, Sanchez was fouled by the youngster, leaving the 30-year-old fuming, according to The Sun.
His move to Old Trafford from the Emirates has been nothing short of disastrous thus far but Ole Gunnar Solskjaer has told him he remains a part of his plans.
The Chile international is, however, behind his team-mates in terms of his schedule as he continues to build up his fitness and has worked away from the squad in a bid to get up to speed.
He was left out of the squad against Chelsea but he is back in training and can be expected back in action sooner rather than later.
Greenwood, 17, came off the bench during the 4-0 win over Frank Lampard’s side on Sunday and is set to get a chance to shine in the first team this season.
Solskjaer is determined to give young players opportunities to state their case for a spot in the first team, but he has left the door open to former Barcelona attacker Sanchez to finally show his best form in a United shirt.