For United's Casemiro, it was nothing short of a nightmare.

Salah scored for the seventh straight game at Old Trafford and also provided two first-half assists for Luis Diaz in United’s latest humiliation at the hands of its fiercest opponent in what is historically the biggest match in English soccer.

Make that 15 goals in all competitions for Salah against United since he joined Liverpool in 2017 and he was regaled with songs by the vocal visiting contingent in the final moments of a one-sided match.

By that time, Casemiro was off the field — and maybe wondering what his future holds at United.

The 32-year-old Brazil midfielder was at fault for both of Diaz’s goals — first because of a sloppy pass, and then after being dispossessed — and he was substituted at halftime for a 20-year-old rookie in Toby Collyer.

His performance came two days after United spent $55 million on Manuel Ugarte, a Uruguay defensive midfielder who arrived from Paris Saint-Germain as likely the long-term replacement for Casemiro.

That was part of a summer outlay of $240 million by United after deciding to keep Erik ten Hag as manager, despite a disappointing eighth-place finish in the Premier League last season.

On this evidence, nothing has changed for the team that was once the biggest in Europe but which hasn't won the league since 2013, the last season of Alex Ferguson.

United has lost two of its three league games so far this season, winning the other one — against Fulham — thanks to a late goal.

In contrast, Liverpool has won all three matches without conceding a goal. It's quite the start to life at Anfield for Arne Slot, with Liverpool enjoying a seamless transition after nine trophy-laden years with Jurgen Klopp.

The only other team with nine points from nine is defending champion Manchester City.

The win would have given Liverpool extra satisfaction because the team's season was ruined at Old Trafford in the 2023-24 campaign, after losing in the FA Cup quarterfinals and dropping vital points in the league title run-in.

The season before, Liverpool beat United 7-0 at Anfield while it enjoyed 4-0 and 5-0 wins over United in the 2021-22 season.

(For more sports news and updates, follow Ahram Online Sports on Twitter at @AO_Sports and on Facebook at AhramOnlineSports.)