Ralf Rangnick branded Manchester United's performance in their 4-0 defeat to Liverpool as "embarrassing, maybe even humiliating" and said as many as 10 new players might have to arrive in the club's rebuild.
United were hammered at Anfield on Tuesday night, just six months after Liverpool won 5-0 at Old Trafford.
Rangnick pulled no punches in his postmatch assessment and said the new manager -- likely to be Ajax Amsterdam coach Erik ten Hag -- would have to rip up the squad in the summer.
"It is embarrassing, it is disappointing, maybe even humiliating," Rangnick said. "Especially the first half we were just not up to it.
"Against a team like this if you want to have a chance you have to cause them problems and make use of those few counter-attacking moments ourselves and we couldn't, and that's why we lost 4-0.
"If you analyse the team, it needs a rebuild. There are six, eight maybe 10 new players and before you sign them you need to be aware what kind of football does the new manager want to play and then fit into that kind of profile."
While United are on course for their worst ever points total in the Premier League era, Liverpool are still in the hunt for an unprecedented Quadruple having won the Carabao Cup and booking spots in the FA Cup final and Champions League semifinals.
Liverpool's win saw them move into first place ahead of Manchester City in the table, with Pep Guardiola's side due to play Brighton & Hove Albion at the Etihad Stadium on Wednesday where they could retake the lead in the Premier League with a victory.
"They have better players than we have, and this was really reflected by the result today," added Rangnick of Klopp's Liverpool. "There will be a rebuild for sure, that was obvious in the first three or four weeks for me. For us, it is extremely embarrassing. We just have to admit they are better than us."
Mohamed Salah, who scored twice for Liverpool against United, said the visitors had made life easy for them in the match by giving up the ball in advantageous positions.
"They make our life easier in the midfield and in the back, they always try to give us the ball in a one against one situation so it makes our life much easier," Salah said. "When we defend we had a clean sheet here and a clean sheet there, so they make our life easier.
"We just want to score one goal and once we get the first, go for the second, once we get the second go for the third. It was a top performance from us here and away also. Hopefully carry on like this."
United midfielder Bruno Fernandes agreed with his manager that the performance was well below the standard expected by the club's supporters.
"The fans don't deserve us to play this way. They deserve more from us. The way they stay and applaud us, they deserve more. We have to raise our level higher," said Fernandes, who rejected the idea that the players were not trying.
"I think everyone runs. I think there is effort from everyone. I don't think someone does not give 100%. We have to do it for ourselves, the clubs, the fans and everyone.
"We have to say things but that is kept in the dressing room. Now it is over we have to think of the next game."
The Portugal playmaker said the difference between the two teams was evident.
"Liverpool is ready for the title. We are not. I don't need to be here saying about the difference of the level. We have to look at ourselves, from top to bottom and understand what is going wrong," he said.
United slipped to sixth in the Premier League and are three points behind fourth-placed Tottenham Hotspur, having played a game more.
"We are competing until the end," Fernandes said. "Nobody can put down and think it is over. We have something to fight for."
Information from Reuters was used in this story.