MANCHESTER, England -- Arne Slot extended his 100% winning start as Liverpool manager with a 3-0 victory against Manchester United at Old Trafford on Sunday, putting manager Erik ten Hag under renewed pressure at the club.

Two first-half goals from Luis Díaz -- Trent Alexander-Arnold also had a first-half goal ruled out for offside by VAR -- and a second-half goal from Mohamed Salah sealed an easy win for Liverpool, who moved to joint top of the Premier League alongside Manchester City on nine points. United's defeat was their second in three league games this season, and sees Ten Hag's side go into the international break with question marks over their ability to challenge for Champions League qualification after spending more than 180 million on new players over the summer.

Ten Hag humiliated by Slot

Ten Hag, who is now entering his third season as Manchester United manager, was humiliated by Slot, who was serving just his third game as Liverpool boss. The buildup to this game was dominated by the story of the two Dutch coaches who have made the transition from the Eredivisie to take charge of the Premier League's two biggest clubs, but it was Slot who looked more like a manager who has been in charge for years, rather than Ten Hag.

Last season's FA Cup win against Manchester City at Wembley kept Ten Hag in a job at Old Trafford, but all of the issues that threatened his position last year resurfaced in the defeat against Liverpool.

For too long under Ten Hag, United have been overrun in midfield, have lacked threat up front and also struggled with their full-backs. Some of that can be put down to personnel, but the players have changed over time and the problems have not gone away.

Casemiro lacks the mobility to perform at Premier League level, but Bruno Fernandes plays so far forward that it leaves huge gaps in the centre of the pitch. Ten Hag has had plenty of time to correct that flaw, but he hasn't, and it is why Liverpool dominated the central third of the pitch.

Up front, Ten Hag persevered with the out-of-form Marcus Rashford, who has yet to score this season. Summer signing Joshua Zirkzee also looks well short of match fitness and speed of thought, and Ten Hag's substitutions -- he left Rashford on for the full 90 minutes but withdrew the impressive Alejandro Garnacho -- invite further scrutiny.

Ten Hag said last week that Slot inherited a better team at Liverpool than he picked up at United, but Ten Hag has now had plenty of time to make a difference. This performance was a worrying one for the former Ajax coach because it looked like a case of new season, same old problems. -- Mark Ogden

Casemiro's disastrous 45 minutes

Casemiro has two years left on his contract at Old Trafford, but this may go down as the day his Manchester United career ended.

As the first half drew to a close -- Liverpool leading 2-0 -- the Brazilian humped a hopeful ball forward to nobody in particular. There were loud groans in the stands, and Garnacho, the nearest United player to it, threw out his arms in frustration.

It was the last act of a truly dreadful performance with Ten Hag deciding at the break that Casemiro couldn't be allowed to continue. In his place, 20-year-old Toby Collyer was thrown on for his first competitive appearance. Really, Ten Hag wanted to use Manuel Ugarte, the 50 million signing from Paris Saint-Germain who was watching from the directors' box.

Ugarte, the fiery defensive midfielder, was presented on the pitch before kickoff but wasn't registered in time to play. After Casemiro's horror show, it's probably safe to say he'll be involved when United play next against Southampton after the international break.

In just 45 minutes, Casemiro managed to lose possession 13 times and make two mistakes directly leading to goals. First, he gifted the ball to Ryan Gravenberch in midfield in the build-up to Díaz's first goal. Then, he was dispossessed on the edge of his own penalty area moments before Díaz swept in Salah's cross for No. 2. In between, there was mistake after mistake and one throw-in that bounced off his shin and back out of play.

It was a performance that will live long in the memory -- for all the wrong reasons. -- Rob Dawson

Salah haunts United again

Salah has now scored in his past five Premier League games for Liverpool at Old Trafford. No other player in the Premier League era has scored so regularly against Manchester United on their home turf.

It wasn't just Salah's second-half goal that marked his performance for Liverpool, though. He also created the first goal for Díaz and was close to scoring a second within a minute of making it 3-0.

The 32-year-old said after the game that this will be his last season at Liverpool with his contract due to expire in the summer. Plenty can happen between now and May, so it would be foolish to discount the prospect of Liverpool and Salah thrashing out a new contract.

If he does leave Anfield, though, the sense of relief at United will be almost as big as the feeling of loss at Liverpool.

The former Chelsea and AS Roma forward has made himself a Liverpool legend during his seven years at the club and will go down as one of the greatest Premier League forwards, comparable to the likes of Thierry Henry, Eric Cantona, Didier Drogba and Erling Haaland. -- Ogden

Liverpool's midfield purrs, United's porous

As bad as Casemiro was, he could be forgiven for looking enviously at the slick way Liverpool's midfield operated.

Both teams started with three men in midfield: Casemiro, Fernandes and Kobbie Mainoo for United, and Gravenberch, Alexis Mac Allister and Dominik Szoboszlai for Liverpool. Where Slot's players looked like cogs in a well-oiled machine, though, the red shirts of United resembled crisp packets blowing aimlessly in the wind.

Gravenberch was excellent, winning 100% of his tackles and recovering the ball six times. He was also allowed to roam forward, and when he did, Mac Allister took up position in front of the back four. When Mac Allister went forward, Gravenberch dropped in.

Too many times Casemiro was caught upfield and looked around to see that Mainoo and Fernandes had followed him forward. One pass from Virgil van Dijk after just six minutes took out most of United's midfield, and they were fortunate that Alexander-Arnold's goal was ruled out because of offside.

On another day, Mainoo might have been sent off before half-time after flying into two challenges as he tried desperately to cover the gaping holes in the middle of the pitch.

At one point Sir Jim Ratcliffe had his head in his hands, and the worry for United's new co-owner is that Slot has his midfield purring after just three games while the structural issues in Ten Hag's team have been evident for more than 18 months. Oh, and Slot didn't even get the midfielder he wanted in the summer because Martín Zubimendi decided to stay at Real Sociedad. -- Dawson

New United regime look glum, Liverpool run riot

There have been big changes at United in recent months with Ratcliffe's INEOS group taking charge of football operations from the Glazer family, the club's majority owners. Ratcliffe has hired Omar Berrada as CEO, Dan Ashworth as director of football and Jason Wilcox as technical director, and all four men were in the directors' box as Liverpool tore United apart.

Berrada has arrived from Manchester City with a reputation for wanting quick results and a clear sign of progress, while Ashworth and Wilcox have spent their first summer being busy in the transfer market, signing and offloading several players. United were so bad against Liverpool, though, that they will be wondering how long it will take for the situation to turn around for the better.

Ten Hag won't be in any danger just yet, but if United continue to struggle when the October international break comes around, the availability of managers such as Gareth Southgate and Thomas Tuchel will give the new bosses options if they decide to make a change. -- Ogden

Liverpool's bold 4-2-4 succeeds, but will it work against the best?

Slot went for a bold 4-2-4 formation, with Gravenberch and Mac Allister covering the central third of the pitch for Liverpool. Both players impressed and dominated their area of the pitch, but their opponents were in disarray in midfield. At times, Liverpool had the midfield to themselves.

The formation worked against United, but it is unlikely that Slot can, or will, deploy the same game plan against opponents such as Manchester City or Arsenal. Slot was rewarded for being bold against United, but City and Arsenal will offer a much greater threat in all areas of the pitch, so expect a more solid Liverpool midfield in those games. -- Ogden