Ole Gunnar Solskjaer has warned that only players with the right attitude will stay at Manchester United next season after rivals Manchester City inflicted a seventh defeat in nine games.
Second-half goals from Bernardo Silva and Leroy Sane took City back to the top of the league with a 2-0 derby win, one point clear of Liverpool with three games left to play, and highlighted the gulf in class between United and the Premier League leaders.
Solskjaer won 14 of his 19 games while in caretaker charge of the club, but it is now five defeats in seven since he was handed a three-year contract, highlighting the scale of the rebuilding job ahead in the summer.
Before the match, former United captain Roy Keane hit out at "bluffers" in the United squad who were not capable of getting the club back to the top, warning they had thrown Jose Mourinho under the bus and adding "they will do exactly the same to Ole".
Asked about Keane's comments, Solskjaer did not dispute them.
"With Roy, I've always had a great relationship with him and I value his opinion very highly," Solskjaer said. "We played together for many years and he's a Man United guy. He hurts just as much as anyone else connected with the club.
"We're so far behind City and it's my job that when we come back in pre-season that I have the right characters in and around the club because it should never be allowed.
"When you're at Man United, the highlight will be on you and you've got to make sure you come into work every single day with the effort like today. That's your duty."
Though he would not single out individuals, saying this was "not the time to point fingers", Solskjaer was clear his players needed to understand the responsibility of playing for United.
"That's what you sign up for when you play for Man United," he said. "The expectations, the history. But we are where we are. Step by step, we need to make sure we're on the right track. We can't linger along for many years.
"You should be at 100 per cent and it's my job to have a group and a squad and a team that will do that for us. That's my job. Who wants to sacrifice enough to be here?"
While Solskjaer is facing a fight to salvage United's season, Pep Guardiola and City remain in control of the title race.
Though Tottenham ended their Champions League dreams, Guardiola's men have responded with crucial Premier League victories over Spurs and now United.
The Catalan also claimed yet another record as he became the first manager to win on his first three league visits to Old Trafford.
"To come here to the most prestigious team in England over the last 20 to 30 years and win for the third time in a row, with a lot of pressure, was fantastic, because we know that if we lost, nothing," he said.
"The (players) have my incredible respect because it's massive what they have done this season."