Jurgen Klopp‘s men made the trip to Old Trafford for a fourth-round clash, looking to overcome an awful run of form.
While Liverpool ultimately crashed out of the competition, the Reds were improved overall, dominating for periods of the game.
Mohamed Salah and Mason Greenwood traded goals in the first half, before Marcus Rashford pounced on a mistake from Williams, putting United 2-1 up.
Salah equalised for the Reds, but just as they managed to take control of the game, Bruno Fernandes fired home a match-winning free-kick.
Salah (7.5) earned the highest average for the first time in a while, as he showed signs of returning to his best at Old Trafford.
The Egyptian took both of his goals in typically clinical fashion, taking his tally for the season to an impressive 19 in all competitions.
TIA’s Jack Lusby felt Salah was “significantly less wasteful than in recent weeks,” as highlighted by his two deadly finishes.
Ian Doyle thought the 28-year-old “came alive” as the minutes ticked by, in his most promising display since Crystal Palace away on December 19.
Firmino (7.0) was next up in the ratings, with the Independent‘s Karl Matchett of the opinion that it “suited him to have another forward closer to him in the middle.”
FotMob noted that Liverpool’s No. 9 created three chances overall, also winning three of his four duels and making seven recoveries.
Curtis Jones (6.0) completed the top three, with Lusby describing the youngster as “tidy and inventive” in a left-sided role.
Unsurprisingly, it was Williams (4.1) who got the lowest average, as the 19-year-old’s shortcomings were exposed horribly.
It was a “difficult afternoon” for the centre-back, according to Doyle, and Matchett concluded that it was a “bit of a nightmare overall.”