United may be returning to winning ways on the pitch but away from it, there remains problems behind the scenes.
News broke of a training ground row between two players after an incident in training.
According to The Sun, Sanchez took major issue with rising star Greenwood – despite only just returning to the club.
The Chile international has been out with a hamstring injury that he has only just recovered from.
The 30-year-old was injured in the Copa America third-place play-off against Argentina, lasting just 17 minutes.
It was the latest setback in a long list on injuries that have plagued his United career.
And after Greenwood fouled the former Arsenal man in training, Sanchez lost his rag at the youngster – with The Sun reporting that angry words were exchanged between the pair.
Ole Gunnar Solskjaer is looking to oversee a return to glory with United after a poor season last year.
The Red Devils finished sixth in the Premier League last campaign but a good pre-season has rekindled hope.
And that optimism was buoyed on the first day of the new season after a 4-0 thrashing of Chelsea at Old Trafford.
It laid down a marker against one of their top six rivals while also showcasing Solskjaer’s style of play.
United were quick, hungry and clinical on the counter-attack after taking the Blues apart on Frank Lampard’s debut.
Solskjaer has insisted that Sanchez is part of his plans but early indications suggest that Greenwood may be ahead of him in the pecking order.
The ex-Barcelona forward is already behind by nearly a month after being setback by his injury.
And Greenwood, 17, is one of a troupe of highly-rated teenagers at the club that the manager is keen to incorporate.
It follows from a summer of transfer business where the Norwegian has demanded young, British talents to bolster his squad.
United chief Ed Woodward adhered to the coach’s wishes by supplying him with Daniel James, Aaron Wan-Bissaka and Harry Maguire.
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