The result at Anfield was an immediate response to the disappointment of defeat at Old Trafford last time out, and lifted the Reds back up to third in the Premier League table.
Here are five talking points from a snowy evening in L4…
The latest landmarks for Mo
Salah’s fourth strike of the match was his 36th of 2017-18, which set a new record for the most goals scored in a debut season for Liverpool, overtaking Fernando Torres’ tally of 33 in 2007-08 – with at least nine games remaining this term.
What’s more, his fourth-minute opener – achieved through a trademark drop of the shoulder and cool finish – brought up another milestone for the unstoppable Egyptian.
The No.11 is only the third different player to score at least 25 times in the Premier League in a single campaign for the Reds, emulating Robbie Fowler and Luis Suarez.
The former did it twice, bagging 28 goals in 1995-96 and 25 the previous season, while the latter plundered 31 as Liverpool claimed second place in 2013-14.
Bobby breaks new ground
Firmino achieved a personal feat of his own when he met Salah’s Kop-end cross at the outset of the second half with an impudent flick past Orestis Karnezis and into the bottom corner.
It was the Brazilian’s 23rd effort of the season, the most he has ever notched in a single campaign during his whole career to date. His previous best came for Hoffenheim four years ago.
The No.9 has played more games (125) and scored more goals (46) than any other Liverpool player since Jürgen Klopp took charge of the club in October 2015.
Andy Robertson puts it on a plate
Upon tapping home his second of the game, Salah’s first glance was in the direction of the left flank from where the stunning assist had originated.
Specifically, his sights were on Robertson, who had picked out his teammate with an unerring, low delivery across the area which encapsulated the Scot’s outstanding form.
It was the left-back’s 18th start in 22 matches since the beginning of December, having featured on only three occasions beforehand, and another display of the highest quality.
Half-a-dozen hauls of five or more
The goals racked up against Watford marked the sixth occasion this season when Klopp’s men have registered five or more in one game.
Seven were put past both NK Maribor and Spartak Moscow in the Champions League group stage, while Brighton & Hove Albion and Swansea City were on the receiving end of five in the Premier League before FC Porto suffered the same last month.
There have been half-a-dozen four-goal showings along the way, too, as Liverpool continue to strike fear into opposition defences at home and in Europe.
Taking advantage of rivals’ absence
Winning before an international break is always important but in the case of this match, perhaps the result was even more vital than usual.
The three points lifted the Reds above Tottenham Hotspur to third in the table on a weekend when Spurs, Manchester United and Chelsea are in FA Cup rather than Premier League action.
Indeed, the Reds will have played another league fixture before any of those three sides – and could therefore take second place with victory at Crystal Palace on March 31.