Salah hit the Reds' first two goals of the weekend against the hapless Hornets, before his Brazilian strike partner swooped to make it three before the hour mark. The Egypt international went on to complete his hat-trick in the 77th minute and added a fourth before the end as Jurgen Klopp's side strolled to three points.
Firmino's strike, moreover, was assisted by none other than Salah, while two of the Egyptians goals came courtesy of Mane, cementing the trio's reputation as one of the Premier League's finest forward partnerships.
The only duo that can match Salah and Firmino's record of seven assists between each other is Mane and Salah, while the rest of the league lags behind.
Firmino has fed Salah three times, while the Egyptian's latest assist means he has repaid the favour on no less than four occasions.
Mane, meanwhile, teed up his team-mate twice on Saturday to make it six assists for him overall, with Salah providing for the Senegal international once.
Chelsea's Cesar Azpilicueta and Alvaro Morata and Man United pairing Romelu Lukaku and Anthony Martial lie in second place with six mutual assists.
7 - Roberto Firmino (3 assists) and Mo Salah (4 assists) have combined for more goals than any other duo in the Premier League this season. Telepathy. pic.twitter.com/iyeQzXjBaM— OptaJoe (@OptaJoe) 17 de marzo de 2018
It has been a season to remember for both Salah and Firmino, as they have spearheaded the Premier League's second-best attack behind Manchester City.
Salah has hit a total of 28 goals so far, with his four on Saturday taking him clear of Harry Kane as the current top scorer.
With 14 of his own league strikes, meanwhile, and 23 overall this campaign, Firmino has already surpassed his previous season-best in both the Premier League and in all competitions, beating the marks set in 2016-17 for the Reds (11 Premier League goals) and back in 2013-14 with Hoffenheim (22) respectively.