Ole Gunnar Solskjaer is indelibly associated with perhaps the greatest day in Manchester United’s history. Sadly for him, he is now a byword for a historic low. As Liverpool got their biggest ever win at Old Trafford, Jurgen Klopp could celebrate the latest in a series of extraordinary scorelines he has overseen and a rampant Mohamed Salah pressed his case to be recognised as the world’s finest footballer with a hat-trick, United were a pathetic excuse for a team. This was a humiliation and an embarrassment, the sort that will hurt the United fan in the beleaguered Solskjaer. Saturday was the 10th anniversary of the 6-1 defeat to Manchester City, but that featured three late goals. This was the first time United had ever been 4-0 down at half-time in the Premier League. It was Solskjaer’s worst day: worse than Young Boys of Bern or Istanbul Basaksehir or Sheffield United or losing 6-1 to Jose Mourinho’s Tottenham. It was a game to flag up the question if he can possibly be allowed to continue. As Klopp continued to illustrate the difference a high-class manager can make, Solskjaer has never looked so out of his depth. His back four cost £190 million ($261.5m) and were a shambles. The entire team were a rabble. A couple of the supposed superstars of a club increasingly defined by big names were a disgrace, too. Paul Pogba came and went in 15 minutes, the substitute sent off. Booked for a lunge at Naby Keita, it was upgraded to a red card when Anthony Taylor reviewed it on the monitor. Another of United’s superstars should have exited in ignominious fashion before then. Cristiano Ronaldo escaped with a caution for a malicious kick at Curtis Jones; the officials exacted a different form of punishment when Ronaldo thought he had scored, only for VAR to chalk the goal off. The loss of Keita, stretchered off after a superb display, and James Milner mean Liverpool now have five injured midfielders and were the only blots on a near-perfect day for Klopp. Liverpool were outstanding. Salah can seem to reach new heights by the week and he became the first visiting player to get a hat-trick at Old Trafford since the Brazilian Ronaldo in 2003. He tormented Luke Shaw, making one of Euro 2020’s best left-backs look like an amateur. He is creator as well as scorer and the pivotal goal featured a Salah assist. After Bruno Fernandes blazed over when Liverpool’s defence were dragged over to their right, Liverpool produced a similar move that a different finish. Each of Liverpool’s front three was involved before a midfielder scored. Salah fed the overlapping Keita. He slotted a shot past David de Gea for a second fine goal in a week, following his spectacular strike against Atletico Madrid. The second came courtesy of catastrophic defending. Harry Maguire and Shaw confused each other as neither got the ball. Trent Alexander-Arnold did instead, delivering the low centre that Diogo Jota converted; had he not scored, a similarly unmarked Milner was waiting to apply the finishing touch, but Klopp got a reward for preferring the Portuguese to Sadio Mane. Then Salah took over. He provided an emphatic finish from Keita’s low centre to overtake Didier Drogba and become the highest-scoring African in Premier League history. He sidefooted in the fourth after a pass from Jota. His hat-trick was prodded in after accelerating on to Jordan Henderson’s lovely pass. Pogba had lost the ball in the centre circle, his first notable contribution after coming on; bizarrely, Solskjaer had substituted Mason Greenwood, United’s brightest attacker in the first half, to replace him with the Frenchman. In the stands, Alex Ferguson shook his head, stone-faced while Kenny Dalglish beamed with glee. Liverpool’s greatest player had much to savour; Firmino was irrepressible and irresistible, albeit aided by United’s inability to track anyone. Salah was electric and exceptional. The surprise selection Ibrahima Konate excelled in defence. Liverpool eased up in the final half-hour, perhaps showing sympathy to Solskjaer. Their fans showed no such mercy. They taunted the United manager with taunts of “Ole’s at the wheel.” But for how much longer?