Luis Diaz scores twice in Liverpool's dominant win over Manchester United | Premier League

It was hard to imagine a more perfect afternoon for Arne Slot, or more heartbreaking for Erik ten Hag, who, after just three games in the Premier League season, is back in familiar territory; the vultures circling, his credentials as the Manchester United The manager is under even greater scrutiny.

Slot had won his first two games in charge of Liverpool (against Ipswich and Brentford), but this was supposed to be the acid test. It wasn't, United were so weak, and their first-half disaster was exemplified by a horrible performance from Casemiro. Things didn't improve from then on, and the only consolation was that they avoided a real thrashing, one that would rival that of the Red Devils. The 7-0 at Anfield Two seasons ago, Liverpool had the opportunity to score a similar number of goals.

A coach can only defeat what is in front of him and Slot and his team did so with great mastery. Their superiority in all aspects was almost grotesque and when Luis Díaz scored his second goal for 2-0 towards the end of the first half, the question of eventual victory became nothing more than a doubt.

They were content with one more goal from Mohamed Salah – the eternal thorn in United’s side – and Slot could say more than just a dazzling attacking performance: it was the third clean sheet in three games for his team. Jürgen Klopp had failed to beat Ten Hag’s team at Old Trafford, but Slot was able to send a very clear message by becoming the first permanent player Liverpool manager who won his first league game against United since Bob Paisley in 1975. His team are intent on being in the title hunt.

By the end of the game, Old Trafford was half empty and those who remained were too stunned to boo. The television cameras had made the obligatory cuts to show a serious-faced Sir Jim Ratcliffe in the stands. United's minority owner has a lot on his mind, as does everyone connected with the club.

The match was loud and raw at first, with United fans taking the lead as Ten Hag had demanded, but it wasn't long before those who had travelled from Liverpool made themselves heard and enjoyed themselves.

The game was heated from the start and the away side were in ecstasy when Trent Alexander-Arnold scored from close range before a VAR intervention brought them back to reality. Salah was offside when he touched Diaz's pass. The move had been started by Ryan Gravenberch's back-heel. The United defence, in which Matthijs de Ligt made his debut, was torn to shreds. It was a sign of things to come.

Liverpool were exuding intensity, pressing high, pushing forward to win possession. They took over the midfield, where United were extremely open, chasing shadows. From the start it was easy to worry about Casemiro's lack of speed on the ball. Or without it. Sadly for United's holding midfielder, the first half would become a personal nightmare for him.

Liverpool's breakthrough left them with a tough image, but also highlighted their rapid transitions from defence to attack. Casemiro received a first-time pass intended for Kobbie Mainoo that failed to reach Gravenberch, and Liverpool smelled blood. Gravenberch passed to Salah on the right and there were men at the far post. Sound familiar? Dominik Szoboszlai couldn't get to Salah's cross, but Díaz did.

Casemiro had dangerously followed Alexis Mac Allister in the 11th minute and was lucky not to be booked; it was the only chance he had. The bad moments he had can hardly be mentioned, such as losing his balance and the ball on the touchline, heavy touches and many inaccurate passes.

Ten Hag sent Toby Collyer on to warm up before the end of the first half and by then the score was 2-0, with Casemiro again at fault. Liverpool knew they could make things happen if they got men around Casemiro and by the time Diaz challenged him as he hesitated, Liverpool were already out. Casemiro wanted a free kick but there was none. Liverpool’s execution was again ruthless: Mac Allister passed to Salah who quickly slotted it inside for Diaz. He had found space; the finish was low and deadly.

Liverpool could have had more before the break. Szoboszlai failed to connect clearly with Andy Robertson's cross, while De Ligt made a valuable one-on-one challenge to thwart Diogo Jota's effort. United's only chance was a Noussair Mazraoui shot that Alisson cleared away.

When Collyer came on for Casemiro at the start of the second half, it was the 20-year-old's first first-team game apart from his substitute appearance in the Community Shield. United's new midfield signing Manuel Ugarte, who was paraded to cheers before kick-off, had not been signed in time.

Liverpool were in the mood to continue suffering and it was impossible to think they wouldn't. United were obscenely complacent. The dreaded no-go zone between their defence and midfield was back and every time Liverpool attacked it, the sirens went off.

The third goal came after Mac Allister stole the ball from Mainoo and once again Liverpool were ahead, with United unable to resist. Szoboszlai set up Salah to score and Liverpool could have added two more goals straight away. Lisandro Martinez lost the ball and was fortunate that Salah picked the ball up after cutting inside as the Liverpool striker saw his curling shot deflect just wide of the far post.

United faced total humiliation and Old Trafford was a haunted place, with boos rumbling as Ten Hag replaced Alejandro Garnacho with Amad Diallo. It seemed the fans wanted him to take off the ineffective Marcus Rashford. Frankly, Ten Hag could have given anyone a good beating.

United had chances in the second half. Joshua Zirkzee (another debutant) came close to scoring three times, but it was little more than a footnote. More telling was Szoboszlai's miss in the 79th minute, when he simply tried to be too clever. Not surprising, because it had been so easy for his team.