Booed at half-time, booed at full-time and even during the game, Sunday's loss to Liverpool was a miserable day for Manchester United and manager Erik ten Hag.

Arne Slot's side were 3-0 up with an hour gone, prompting many home fans at Old Trafford to leave long before the final whistle.

But it could arguably have been even more damaging.

"Liverpool could have been 5-0 up since they went 3-0 up," said former Manchester United defender Gary Neville on Sky Sports during the game.

"They are getting absolutely mauled."

The club's former captain, Roy Keane, was equally dismayed by what he saw unfolding at Old Trafford.

"They were absolutely shocking," he said on Sky Sports.

"Every time Liverpool went forward, they looked like they were going to score.

"There's been a lot of PR the last few months about plans for the stadium. But in a big game today against Liverpool, United didn't turn up.

"For a game like this to be over after an hour, it's hard to accept."

Ten Hag's future had become increasingly uncertain as last season went on but, after beating Manchester City to win the FA Cup in May, the club's hierarchy decided to stick with the Dutchman after conducting a review.

With some exciting young players at the club, Ten Hag has stressed that Manchester United are in a transitional period, but the booing from their fans would suggest they, understandably, believe their side should be closer to Liverpool.

Manchester United finished 22 points behind Liverpool last season, and there was little to suggest on Sunday that they will not be as far behind as that again this term.

"Liverpool fully deserved their victory," added Neville.

"It was a sobering day for Erik ten Hag, his players and for the new ownership sat in the stand en-masse, looking at it and thinking whether they're on the right path. That's the question they have to ask in the next few months."

The statistics from the game would suggest there wasn't much in it. Both had three shots on target, while it was Manchester United who edged possession.

"The statistics don't tell the story," added Keane. "It was far from an even game.

"Liverpool were very good and very efficient. They looked stronger and they looked fitter. You can try to dress it up a little bit but United were shocking.

"They are making the same mistakes as last year."

The defeat means Manchester United have now lost three of their last five Premier League home games against Liverpool, as many defeats as across their previous such 18 matches.

United have also lost two of their opening three matches of a Premier League campaign for the third time in the last five seasons, with Ten Hag the only manager to suffer that fate twice with the club in the competition.

"It was brilliant from Liverpool," former Manchester United striker Dion Dublin said on BBC Radio 5 live.

"United are still miles off it. Liverpool worked so hard out of possession and United looked all over the place. The passing and shape was terrible."

Perhaps summing up Manchester United's day to forget was the performance of midfielder Casemiro.

Once considered one of the best in the world in his position, the Brazilian - a Champions League winner with Real Madrid - was taken off at half-time after making two costly mistakes in the first half.

His loose pass was intercepted seconds before Luis Diaz opened the scoring and then was tackled by Diaz before he got Liverpool's second.

"Leave the football before the football leaves you," Carragher said.

"He's had such a great career and won everything you can possibly win, and it is a sad sight seeing what he's going through out there."

Neville added: "I have to say he's lost his confidence a little bit.

"For Casemiro, someone who has won Champions Leagues with Real Madrid, it can happen to you in games."

After Manchester United's board conducted their end-of-season review, they triggered a one-year extension to Ten Hag's contract that will keep him at the club until 2026.

This is his third season at Old Trafford, guiding them to a third-place finish in 2022-23 and then eighth last season.

"I don't think anything is going to change in terms of the football [at Man Utd]," added Carragher.

"Ten Hag said in his interview 'we will see where we are at the end of the season'.

"I would be surprised if he is still there at the end of the season."

Neville said: "Not just Erik ten Hag, but every manager has struggled.

"It is a time for a bit of calm. The international break [is here] which is well needed for Manchester United.

"Erik ten Hag needs to get the club into a position challenging for Champions League near Christmas or he will be in trouble."