Liverpool maintained their flawless start under new manager Arne Slot as they outclassed woeful Manchester United at Old Trafford.
The visitors were on a different level to United in a win so comprehensive that it will bring renewed scrutiny on Slot's fellow Dutchman Erik ten Hag, who survived a summer review to win a new contract following last season's FA Cup win.
Liverpool have barely missed a beat since Slot replaced Jurgen Klopp, recording three straight Premier League wins now without conceding a goal, and this was the most impressive display so far.
Trent Alexander-Arnold had already had a goal disallowed for offside before Luis Diaz struck twice in quick succession just before the interval to put Liverpool in complete command.
Casemiro, who endured a first-half nightmare before being replaced, was the culprit twice as he conceded possession, with Diaz heading home Mohamed Salah's cross at the far post after 35 minutes before sweeping in the Egyptian's pass in front of the Stretford End seven minutes later.
Salah, inevitably, got in on the act with his 12th goal in 15 appearances against United after 56 minutes, beating Andre Onana from Dominik Szoboszlai’s pass.
United had opportunities, mainly through Joshua Zirkzee, but there were only occasional moments of anxiety for Liverpool as they put Ten Hag's side firmly in their place.