Ole Gunnar Solskjaer's team have been inconsistent since then and sit five points adrift of the top four, with injuries affecting their squad significantly in recent weeks.
The club have been hoping to add quality in the January window, but the pressure will continue to mount on Solskjaer if his side are embarrassed by their old rivals on Sunday.
Here, Sports Mole has selected its strongest combined XI from the two squads, using only players available this weekend.
Alisson's arrival at Anfield last season was a crucial part of Liverpool making the leap from top-four contenders to title chasers, while De Gea's excellence between the sticks has covered up for many of Manchester United's failings in recent seasons. However, the Spaniard has not quite hit the same heights over the last 18 months and therefore is just edged out by Brazil's number one.
At full-back the decision is not so difficult to make, with Trent Alexander-Arnold and Andrew Robertson the two outstanding wide defenders in the league. The two of them play a critical role in Klopp's build up and have 14 league assists between them this season.
For United, Aaron Wan-Bissaka is an outstanding defender but does not possess the same attacking quality as Alexander-Arnold, while neither Luke Shaw nor Brandon Williams are at the level of Robertson.
In the centre Virgil Van Dijk is an obvious pick, with the Dutchman perhaps the best centre-back in the world. His speed, composure and technique are on show week after week for the champions elect, while he seems to improve whoever plays alongside him.
Choosing his partner is slightly tougher, with Joe Gomez, Dejan Lovren, Harry Maguire, Victor Lindelof and Joel Matip all in contention. However, given Matip's recent injury troubles, Maguire gets the nod. Maguire does not quite have Van Dijk's ability on the ball or speed, but he has made a solid start at United and is a crucial component in one of the Premier League's better defences.
In midfield, United's Fred edges out Alex Oxlade-Chamberlain for the final slot, with Jordan Henderson and Georginio Wijnaldum nailed-on starters. The absence of Paul Pogba and Scott McTominay, coupled with Fabinho's lack of match sharpness, makes this a slightly weaker lineup than expected, but it is still one that would impress in Klopp's ferocious system.
As they would alongside Fabinho, Wijnaldum and Henderson flank the midfield, while the ever-improving Fred would anchor the trio. The Brazilian was derided early on his United career, but he has become one of their most consistent performers, stepping up during Pogba's absence to lead the midfield.
Up top, Liverpool's front three of Roberto Firmino, Sadio Mane and Mohamed Salah are kept together, with injury doubts over Marcus Rashford preventing him from featuring in this lineup. Rashford has been outstanding for Solskjaer this season and would usually make this team, but his minutes need to be managed more carefully by the Norwegian going forward if he is to avoid further injuries.
Of the Liverpool front line, Mane has been the most prolific with 11 Premier League goals, but it is the work all three of them do in other parts of the pitch that really show their brilliance. Even so, they have scored 28 goals and provided 15 assists between them in the Premier League so far.body check tags ::