Erik ten Hag accused his Manchester United players of an "unprofessional" and "unacceptable" performance as they crashed to a humiliating 7-0 defeat at bitter rivals Liverpool on Sunday.

United's stunning loss ranked as their worst ever defeat against Liverpool and the joint heaviest in their entire history.

Ten Hag's team collapsed after falling behind to Cody Gakpo's opener just before half-time.

Liverpool scored six times in the second half, with Gakpo striking again, while Mohamed Salah and Darwin Nunez netted braces before Roberto Firmino capped one of the most astonishing results in Premier League history.

United boss Ten hag was ashen faced on the touchline as the scoreline kept mounting and he admitted his players had let themselves down badly.

"I think we played a decent first half. One mistake in organisation just before half-time. Second half it was just not us. It was not our standards. We didn't play as a team. It was unprofessional. Yes (I am angry). Definitely," Ten Hag told the BBC.

"I am surprised because I have seen the last weeks and months this team is resilient and has a winning attitude. Second half we didn't have a winning attitude at all. We didn't stick to the plan and we didn't do our jobs.

"We didn't track back and it was really unprofessional.

The incredible defeat came just seven days after Ten Hag's side had ended United's six-year trophy drought by beating Newcastle 2-0 in the League Cup final at Wembley.

'Disappointed and angry'

That result was heralded as the start of a bold new era for United, with Ten Hag praised for transforming a team that finished sixth in the Premier League last term before he arrived from Ajax in the close-season.

But United's wretched display in such a significant game showed how much work Ten Hag still has to do to rebuild a club that hasn't won the title since 2013.

United, who remain third in the Premier League, had already endured an embarrassing 6-3 defeat at Manchester City this season, as well as a 4-0 loss at Brentford.

This was a new low but Ten Hag urged his team to use it as motivation for the rest of the season, starting in Thursday's Europa League last 16 first leg at home to Real Betis.

"We have seen in the past we can bounce back. After Brentford, after Manchester City. This is definitely a strong setback and is unacceptable. I'm really disappointed and angry about it," he said.

"It is a reality check. We have to take this strong."

United midfielder Bruno Fernandes echoed Ten Hag's call for a strong response to the abject surrender on Merseyside.

"It's very frustrating and disappointing. It's sad because it's a really bad result. We came here with a different mindset before the game," Fernandes told Sky Sports.

"We tried to go forward and score goals and we lost a bit of balance. We gave too much space away against this kind of team. We have to avoid that.

"We had setbacks in the past and we have to come back quickly again. This is what Manchester United are about. We can go down but we have to get back up."