It seems as if it was eons ago when Liverpool lost 3-0 to Manchester United at Old Trafford back in December. Manchester United (as has been the story of their season), were clinical with their chances, while Liverpool had large segments of the game when they dominated play, but could not put anything past David De Gea. Now, in the rematch at Anfield, this game may decide who finishes fourth and who is condemned to the Europa League.

Liverpool have not lost (in the Premier League at least) in the calendar year 2015, with their only overall loss coming in Istanbul against Besiktas. Brendan Rodgers has worked magic with his tactics and found spaces for everyone to fit in perfectly to his 3-5-2. Emre Can has become a very solid center-back, Jordan Henderson has blossomed into the all-around midfield Liverpool lacked, and Phillipe Coutinho has become one of the best playmakers in England. And once Daniel Sturridge returned to the lineup, Liverpool had a focal point to their attack that they sorely lacked when he was out. It helps that Simon Mignolet has played some of his best soccer to date, and that the pieces have fit together for Liverpool, despite the turmoil of 2014 and fixture congestion.

Manchester United’s struggles have been well documented, but their fantastic performance against Spurs a week ago has given the Red Devils solely needed confidence. Despite their injuries, lack of form, and similar struggles putting a solid XI together, they are still in fourth despite all of that. Louis van Gaal has spent much of the season tinkering and toying with his formation and XI to find the best way forward for Manchester United, and he may have backed into an answer against Spurs when Angel Di Maria was suspended. Ander Herrera and Michael Carrick were superb, Juan Mata was the creative spark United have lacked so often this season and Marouane Fellaini played the “forward destroyer” role to perfection. All of this allowed United to look as fluid as they ever have and put together their most complete performance of this term.

As they matchup against each other, the key will be flank play. United have gone to a more conventional lineup, and last week were buoyed by the wonderful play of Ashley Young and Antonio Valencia out wide. Liverpool will need to deploy wingbacks that can not only get up the pitch and contribute in attack, but also can contain the pace of those two out wide and contain Di Maria who will certainly play Sunday. This means it’s unlikely Adam Lallana will play as a wingback, so Lazar Markovic or even Raheem Sterling could end up in that role. The possible return of Lucas should help add needed steel to midfield, because as Spurs found out playing light in midfield against United with the Fellaini-Carrick axis is not wise.

United have to step up to the occasion as they have done only on few days out this season. Liverpool can pass United into fourth place if they win and they face a far easier fixture list than their Mancunian rivals do. Van Gaal has been rightly criticized for the way United has played this season at times, but he will earn a heap of goodwill and deserved praise if he wins at Anfield on Sunday.

The winner of this game may well finish in fourth or possibly third this season, and with the Champions League at stake, the intensity of the Liverpool and Manchester United rivalry will be turned up even more. In one of the pivotal games of the season, some may look back on this match at season’s end and saying it was the game that made (or broke) their season.