That’s the verdict of former Premier League star Martin Keown, who has raised doubts about the Portuguese’s recent team selections.
United snapped up Sanchez last week in a swap deal that saw Henrikh Mkhitaryan head in the opposite direction.
The elation they had following that transfer and the subsequent win in his debut subsided last night when United were beaten by Tottenham.
United’s side at Wembley boasted a number of big-money signings, including Sanchez, Paul Pogba and Anthony Martial.
And Keown has now highlighted the problem Mourinho faces with such stellar names now among his ranks.
“The problem Jose Mourinho is finding is that the more good players he gets, the more pressure he is under to deliver results.”
Keown also outlined the two players that he does not feel should be starting together for United.
“I am not convinced that Mourinho knows his best starting XI,” he added.
“Jesse Lingard is playing so well that Mourinho does not want to drop him, but I do not think that Lingard and Paul Pogba can play together.
“Also, with Sanchez playing wide on the left, it leaves question marks over Anthony Martial and Marcus Rashford.
“In the coming weeks, Mourinho is going to have to look closely at his team and their shape.”