Former Manchester United captains Gary Neville and Roy Keane accused Ralf Rangnick's team of giving up in Sunday's 4-1 derby defeat at Manchester City.
United had competed well in the first half, going in 2-1 down at the break, but they looked demoralised after Riyad Mahrez scored City's third and that attitude riled the two ex-skippers.
"Manchester United's response to going 3-1 down has been embarrassing. Ninety-two percent possession for City? They have given up," Neville said on Sky Sports.
"They are walking around the pitch. It's nowhere near good enough. There can be no complaints. City have been absolutely outstanding. But as a Manchester United fan, it's embarrassing. "The scoreline isn't the problem. It's the response to going 3-1 down that's the problem. They have thrown the towel in.
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"At the end of the game, Manchester United finished like an absolute shower. They were a disgrace in the last 25 minutes."
Fellow pundit Keane also focused his criticism on the players rather than Rangnick's decision to play with midfielders Bruno Fernandes and Paul Pogba in attack.
"The manager will be criticised about his tactics, but players not running back when you're playing for Man United is really unacceptable," he said.
"They threw the towel in which is shameful. You need character and personality when you're up against it and after the third goal, it was game over," he added.
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It was only the second defeat in the Premier League for Rangnick since taking over after the dismissal of Ole Gunnar Solskjaer, but Neville said United's recent results had been hiding the reality of their squad's level.
"For the past two to three months, United have been plastering over the wounds, playing against sides that you don't have to be at your best to get a result. The only two teams they've played from the top eight, City and Wolves, have done them - and there's a few tough games coming up," he said.
"The dressing room isn't broken, but it isn't far off. The evidence is there. You find out what it's like when the going gets tough and a lot of them went missing," he said.