Manchester United suffered a fourth defeat in seven games on Saturday afternoon, as the Red Devils fell to a 4-0 defeat at Brighton.
The Red Devils started slowly and got worse at the Amex Stadium, with Brighton dominating almost every area of the pitch.
Moises Caicedo opened the scoring after 15 minutes, and the Seagulls picked up the pace after the break, with Marc Cucurella, Pascal Gross and Leandro Trossard adding to the lead.
The loss followed a comfortable 3-0 win over Brentford last Monday, and Ralf Rangnick was shocked to see his side's performance less than a week later, labelling it 'unacceptable'.
"To start with, it's important that we apologise to our supporters who came all the way from Manchester to Brighton," said interim manager Rangnick.
"We were just not good enough from start to finish. The performance was not only poor, it was extremely poor.
"It was a humiliating defeat and even more so for a team like Manchester United.
"It's not only that you lose 4-0, it was also the way we played and this is just unacceptable, very difficult to deal with and to cope."
The United faithful seemingly turned against their players towards the end of the clash, with fans chanting that some of the squad were unfit to play for the club.
But when asked about his side's commitment and desire, Rangnick was quick to defend his players.
"I have to defend the players," said the German. "I don't think that they are (uncaring).
"I saw them in training. I saw them against Brentford.
"We had a good week of training with good atmosphere, with good focus on the training sessions.
"But I remember me watching the game against Watford away, 4-1 (under Ole Gunnar Solskjaer), who are now relegated, and this looked very similar to what happened today.
"For me, the problem is how to defend as a team. If you do not defend properly, if you give them all the space and time in the world, this is the result."
United now have just one game left in the Premier League before the end of the season, when Erik ten Hag will take charge of the side.
They'll travel to Selhurst Park on May 22 in the season finale, where they'll look to fend off West Ham for sixth position.