Manchester United suffered a 3-1 loss to West Ham United at the London Stadium on Saturday evening to heap pressure on the Portuguese head coach.
The Red Devils are in tenth place in the Premier League table after seven games to leave Manchester United nine points adrift of leaders Manchester City and Liverpool FC.
The 20-time English champions have already lost to Brighton, Tottenham, West Ham in the Premier League this season.
Championship side Derby County were 8-7 winners on penalties in the Carabao Cup last week to crash out of the competition.
Former Manchester United midfielder Scholes delivered his withering verdict on the Red Devils squad following their 3-1 loss at West Ham.
“You talk about effort and that is the first thing you rightly expect from a Man United player or any footballer,” Scholes told to BT Sport. “But I just wonder if the quality is there as well.
“The amount of time we’ve been asking if these players are really good enough. They’re not really showing that they are.”
Manchester United finished in runners up spot last season after placing above Manchester City, Liverpool FC, Chelsea FC, Tottenham and Arsenal.
The Red Devils did end up 19 points behind Premier League champions Manchester City to continue their five-season title drought.
Mourinho’s men will welcome Spanish side Valencia in the Champions League group stage at Old Trafford on Tuesday night.
Manchester United haven’t won the Champions League title since 2008.
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