Manchester United legend Gary Neville accused Ruben Amorim's side of complacency after Monday's defeat to Everton and suggested the result would undermine trust in their head coach.

Despite Idrissa Gueye receiving a remarkable red card for striking his own team-mate Michael Keane early on, Everton held firm for a 1-0 victory at Old Trafford.

United laid siege to the Toffees' penalty area after going behind to Kiernan Dewsbury-Hall's curler, finishing the game with 25 shots and 1.71 expected goals (xG), compared to three shots and 0.21 xG for the visitors.

But they could not find an equaliser, losing a home Premier League game after seeing their opponents receive a red card for the first time ever, after 36 wins and 10 draws.

Amorim's side would have gone fifth in the table with three points, but following their first defeat in six games, they sit 10th with an identical record to that of Everton.

On the Gary Neville podcast, the former United right-back lashed out at Amorim's players and said the result had erased all the good work done in recent weeks.

"We're trying to build a trust in a manager, we're trying to build a trust in a team," he said. "The fans booed collectively at the end. It was loud, and rightly so. 

"That was a really poor performance. It's almost as if you've gone two or three steps forward, everyone's feeling a little bit better, and you've just gone back to the start again.

"You can lose football matches, but you can't lose them like that. That's nowhere near good enough, it's not acceptable."

To make matters worse for United, the defeat came against their former boss David Moyes, who tasted victory at Old Trafford as a visiting manager in the Premier League for the very first time, at the 18th attempt (four draws, 13 defeats).

"It's complacency, and complacency will kill you," Neville continued. "The minute you think, as a football player, that you just have to turn up on that pitch and you're Manchester United and you can play... you're done. 

"It just smelt of complacency. They weren't at it from the beginning. That is a bad one for United. 

"I think they've been a lot better in the last few weeks. That probably takes us back to Brentford away."

Neville's fellow Sky Sports pundit Jamie Carragher, meanwhile, questioned Amorim's decision to keep three centre-backs on the pitch when facing 10 men.

"This is a bad night for the manager. There was an awful long time left in that game [after the red card]," the former Liverpool defender said. 

"I don't understand how you can stick with something so steadfastly in a situation like that when it's basically one guy up front who's not really up front. You don't need three players there.

"It's one of those moments where I think a lot of people will really question the manager on the back of that defeat. The manager will take a lot of the blame for tonight."

United are back in action on Sunday, away to FA Cup winners Crystal Palace, before West Ham visit Old Trafford on December 4.