Luis Diaz and Mohamed Salah both struck in the first half, with Sadio Mane also on the scoresheet after the break, before Sala added a fourth late on.
The Reds will look to bounce back in the hunt for a top-four place with a trip to Arsenal on Saturday lunchtime.
FIRST HALF – HOSTS GO AHEAD
United kicked off in a feverish atmosphere and found themselves a goal down in five minutes. A quick break by the hosts saw Sadio Mane play Salah in behind, before the Egyptian teed-up Ruben Dias to convert from close range in the centre of the box.