Ole Gunnar Solskjaer says Manchester United have to look themselves in the mirror after taking full responsibility for their "embarrassing" 6-1 defeat to Tottenham.
United suffered their joint-heaviest Premier League home defeat as Spurs took advantage of a shambolic collapse to deepen the despairing mood engulfing Old Trafford.
Having played more than an hour with 10 men following Anthony Martial's dismissal, United were put to the sword by a rampant Spurs, who took full advantage as Heung-Min Son and Harry Kane doubles, and goals from Tanguy Ndombele and Serge Aurier, inflicted a humbling defeat on Jose Mourinho's former club.
"It is embarrassing, I hold my hands up, it is my fault. It is not Manchester United," Solskjaer told Sky Sports. "You don't win games by making individual mistakes, errors and a performance like that.
"It was nowhere near good enough. Today is the worst. I can't say any more than that. When you have a defeat like this you have to look yourself in the mirror.
"When we got the start we did, you think you have the game how you want it. But we made bad decisions and then we were two or three down.
"When you are 2-1 down you are in with a chance, 3-1 down a minute later is hard. At 4-1 down, it is about character and personality.
"We had to close their avenues to goal, but we didn't come out with any aggression. There are a lot of wrongs today. We need to look at everything."
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Solskjaer refused to attribute the defeat to Martial's red card, which was issued after Erik Lamela theatrically went to ground after being hit in the face by the faintest of touches from the United forward.
"The red is no excuse," the United boss added. "The boy might be having an operation on his throat though!
"It is a bad reaction from Anthony, but if that (Lamela) was one of my players I'd hang him out to dry going down like that. He shouldn't react like that."
With 24 hours to go until Monday's transfer deadline, the manner of United's defeat drew the club's need for reinforcements into even sharper focus.
United have been linked with late moves for Edinson Cavani and Alex Telles, but Solskjaer insists the responsibility of picking up the pieces from Sunday's defeat to Spurs rests with him and the squad already at the club.
"It is not about getting players in but who is here," Solskjaer said. "We defend as a team, from the front. Whoever we are linked with doesn't mean it is true.
"We need as a group to get a performance as they were after the restart. We were a good defensive team, but we can't be as open as we are today."
Rashford apology - 'I feel horrible'
Marcus Rashford took to Twitter after the match to apologise to United supporters.
"First and foremost I'm a United fan. This is my club. I'm so proud to wear this shirt but there are no excuses, it's just not good enough and to every single fan around the world that tuned in today, I'm just so sorry.
"You deserve so much better than that. I would have stayed away from social media tonight, but you deserve to hear from me during the highs and the lows, there is no hiding. I feel horrible but I promise you we will do better."
Club captain Harry Maguire echoed Rashford, saying on Instagram: "Today was totally unacceptable, we apologise to the fans, you deserve so much more. There's no excuses.
"One thing for sure is that we will do everything we can to put this right. We're all hurting but this is the start of a long season with everything to play for. We must stick together."
Neville: Indecision having psychological impact
Gary Neville labelled the performance "pathetic, spiritless and spineless" before highlighting how the lack of signings brought to Old Trafford this summer is having an impact on players.
"There is no excuse for those players who were out on that pitch today, they were absolutely pathetic," the former United captain told Sky Sports. "Their body language was terrible; it was spiritless and spineless.
"When you've got a squad that lacks resilience and know-how to win games, the off the pitch stuff with Harry Maguire and Mason Greenwood, the darkness surrounding recruitment and not getting players when Liverpool, Manchester City, Chelsea and Tottenham are signing players, the minute Spurs went two goals up it was almost as if all those negative thoughts came and drained every bit of confidence out of them. It's not right, but that is what happened."
When asked whether Solskjaer's position at United could be called into question, Neville replied: "This is almost a repetitive cycle.
"We saw it Louis van Gaal, when he won a cup final and the club pulled out on him just as he was building a half decent squad and team. With Jose Mourinho, they backed out on him in that transfer window a couple of seasons ago having given him a contract.
"I thought Jose was playing a game a few years ago when he said it was an unbelievable achievement finishing second with that squad, but on reflection he is probably right.
"I just feel Ole Gunnar Solskjaer did achieve the maximum with these players but getting them to third last season, there was no way he was going to get to the level of Liverpool or Manchester City.
"It was good United finished third last season, they were on the shoulders of Liverpool and City, but they needed to make sure they got closer. City have spent £150m and Liverpool have strengthened with Thiago and Jota.
"They have pulled away psychologically before the season even started, and the psychological damage of not bringing players in is hamper the current squad. The club's job is to build a title-winning team, those are the standards for Manchester United."