Liverpool reasserted their dominance over Manchester United on Sunday by beating their rivals 3-0 as Mohamed Salah enjoyed another dreamy visit to Old Trafford. 

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 their fiercest opponents in what is historically the biggest game in English football.

When it was put to Salah that it was an easy game for Liverpool, he replied: "I agree with you. I was a little surprised. The game could have finished five or six."

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 game.

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 Uruguayan 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.

For many United fans, once the biggest team in Europe, little has changed since they last won the league in 2013 during Alex Ferguson's last season in charge. 

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