Ole Gunnar Solskjaer apologised to everyone associated with Manchester United and admits the Red Devils were second best all over the pitch in Sunday's humiliating 4-0 loss at Everton.
The Toffees registered their biggest ever Premier League win over United with fine first-half finishes from Richarlison and Gylfi Sigurdsson added to by efforts from Lucas Digne and Theo Walcott after the break at Goodison Park.
It completed a miserable five days for United, who were knocked out of the Champions League quarter-finals by Barcelona on Wednesday, and their chances of making the top four are looking increasingly slim.
"From the start of the first whistle everything went wrong," Solskjaer told Sky Sports.
"I just want to apologise to the fans. They were the only people with a badge on today that can hold their heads high and say they were Man United, because we weren't.
"They [Everton] were better than us at everything. All the basics, we concede [from a] long throw-in we know just stick a head in there. The second goal a corner kick, there so many things we have to do better to get a result because talent has never, ever been enough.
"We just didn't perform and that's more or less all I can say. That was not worthy of a Man United team.
"We put our hands up and apologise to everyone associated with the club."
United's task hardly gets easier with Manchester City visiting Old Trafford on Wednesday as Pep Guardiola's side continue their assault on the title.
Solskjaer, though, sees the derby as an opportunity for his men to right a wrong and insists United can win all of their remaining four games.
"It's the perfect chance for everyone to show [what they're capable of] on Wednesday," he added.
"It's a massive game, not just for us but for the league, we have to perform better than this.
"We need a game of football as soon as we can, we need to get this out of our systems and I think everyone here can say with hands on heart that's nowhere near good enough for a Man United team.
"Me, the staff, everyone knows that. I apologise to the fans, I promise we'll come out Wednesday and give a performance.
"Of course you have to [win all the remaining games], then we might have a chance. It's a big ask, but we can do it, we've done it before, these players here have done it before.
"We are going to give it everything we've got in the last four games, massive games with City and Chelsea coming to Old Trafford, but Old Trafford is where we get best support in the world.
"Football, like in life, things can change quickly, we have to change from bad to good."