Chilean forward Alexis Sanchez was involved in a heated training ground row with teammate Mason Greenwood this as reported by the Sun.
Sanchez who is returning from an injury received a rough tackle by Greenwood with the former Arsenal man said not to have been impressed with the tackle and angry words were exchanged between the pair.
Sanchez 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.
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.
"Alexis has come in and trained well. He's four or five weeks behind the boys and has not played apart from the one behind closed doors here, so I think he'll see this as an opportunity as well to make his mark," Solskjaer said ahead of Manchester United's Premier League opener.
Sanchez was signed by Manchester United from Arsenal ahead of in January 2018 in a swap deal as Henrikh Mkhitaryan moved in the opposite direction. The Chilean star has struggled to live up to expectations as he made only nine appearances for the Red Devils in the last league season.