Ralf Rangnick believes Manchester United are six years behind rivals Liverpool after the interim manager watched his side slump to an "embarrassing" 4-0 defeat at Anfield on Tuesday.
United were outclassed as Jurgen Klopp's side returned to the top of the Premier League. The reverse fixture at Old Trafford was also emphatic, with Liverpool claiming a 5-0 victory in October. As Liverpool continue to pursue a historic quadruple, United are down in sixth place in the Premier League, 22 points behind the Reds, and face a huge task to finish in the top four and qualify for next season's Champions League.
"It is embarrassing, it is disappointing, maybe even humiliating," said Rangnick. "We have to accept they are six years ahead of us now. When Jurgen Klopp came they changed at the club and lifted not just the team but the club and city to a new level. That is what needs to happen with us in the next transfer windows," he said.
The German said that Liverpool had improved under each transfer window after Klopp joined them in 2015 and that had paid off with the squad now containing "25 Formula One racing cars".
Rangnick is not expected to remain in charge of United next season with Ajax's Dutch coach Erik ten Hag widely expected to take over as manager.
With several players out of contract, Rangnick, who also has a role as a consultant at the club, said there was going to be major movement in and out.
"For me, it's clear that there will be, I don't know what, six, seven, eight, maybe 10 new players," he said. "And then before you sign those players, you need to be aware, how do you want to play?
"What kind of football does the new manager want to play and then take it from there and then bring every single player fitting into that kind of profile.
"There will be a rebuild, for sure. But right now, that doesn't help us because we still have another five games to play."
United's Portuguese midfielder Bruno Fernandes was clear that the performance was well below the standard expected by the club's supporters.
Liverpool v Man United player ratings
"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 per cent. We have to do it for ourselves, the clubs, the fans and everyone," he said. "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."
Echoing Rangnick's comments, Fernandes 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. "We are competing until the end. Nobody can put down and think it is over. We have something to fight for."