The Red Devils have made a difficult start to the season despite finishing in second place in the Premier League last term.
Manchester United lost to Brighton and Tottenham Hotspur in their second and third games of the top flight campaign.
The 20-time English champions bounced back with successive victories over Burnley and Watford to turn a corner.
However, it proved to be a false dawn after Manchester United drew 1-1 with promoted side Wolves in the Premier League last weekend.
The Red Devils slumped to a penalty shootout loss to Championship side Derby County in the Carabao Cup third round after a 2-2 draw in normal time.
Jose Mourinho has become embroiled in an internal battle for power with club record signing Paul Pogba, according to reports in England.
However, former Manchester United manager Moyes came down on the side of the Portuguese head coach.
“I don’t think the manager can always take all of the flack,” Moyes told Sky Sports.
“There comes a point where the players need to stand up.”
Manchester United haven’t won the Premier League title since 2013 when Sir Alex Ferguson was still in charge.
The Red Devils will take on Valencia in their next Champions League fixture after a 3-0 win at Young Boys earlier this month.
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