Two tribes at war!
Points and pride at stake when resurgent United face Liverpool
Unused and unhappy, Paul Pogba sat on the bench when Manchester United played Liverpool at Anfield in December.
With the game poised 1-1, Jose Mourinho introduced Marouane Fellaini to his under-performing side at half-time.
The match ended 3-1 and moved Liverpool 19 points ahead of the rivals whose record-breaking manager Alex Ferguson once boasted: "My greatest challenge was knocking Liverpool right off their perch."
Ten weeks later, Mourinho is no longer involved, Fellaini is playing his football in China and, under interim manager Ole Gunnar Solskjaer, Manchester United have lost just one of 13 games in all competitions.
United have risen to fourth in the league and seeking to consolidate their Champions League qualification place.
Sunday's clash at Old Trafford, where a potent mix of ambition and animosity is anticipated, has become one of the headline league matches of the season.
Much more than three points are at stake.
Liverpool are currently on the same points as Manchester City at the top of the league but in second place due to City's superior goal difference.
The perch that has evaded them since 1990 is just a short hop away. Dropped points on Sunday afternoon could allow City open up a morale-damaging gap.
But this is a different Liverpool to the sides that also came close under managers Gerrard Houllier, Rafa Benitez and Brendan Rodgers.
There's an air of optimism around Liverpool and manager Jurgen Klopp is being asked if the fans would prefer to win the Premier League or the Champions League.
Klopp's obvious answer has been the Premier League. That's the glittering prize, the Holy Grail, for all Liverpool supporters.
Those Liverpool fans who'll bring their vocal passion to Old Trafford on Sunday will be heartened to know that imperious defender Virgil van Dijk will be available for selection.
And that Xherdan Shaqiri, the man who scored the two second half goals that sank Mourinho's team, and career, in December, had returned to the bench for the Bayern match and could again play a significant role.
But titles don't come easy.
And it's not forgotten that United have traditionally been Liverpool's Nemesis, the force that's named after the indignant mythological figure who acts as an agent of retribution for those who, getting ideas above their station, display arrogance or excessive vanity.
However, Liverpool can take some positive motivation from knowing that United are likely to still be without the attacking threat posed by Anthony Martial and Jesse Lingard.
When their injuries were originally confirmed, manager Solskjaer gave the impression of a man unperturbed by their absence, calmly promising: "I'm sure we'll conjure up something."
His team duly beat Chelsea 2-0 in the FA Cup on Monday
Liverpool, with their mercurial three-pronged attack of Mohamed Salah, Roberto Firmino and Sadio Mane, would appear to have the more potent strike force.
One that's capable of exploiting a United defence that acquired an unwelcome reputation for being worryingly profligate.
However, having already beaten three top six teams away, Chelsea, Arsenal and Spurs, since Solskjaer took charge, this Man United squad are now as swashbuckling as a Hammer horror movie vampire after an infusion of fresh blood.
Jurgen Klopp knows it. And he's aware of the threat posed by a rejuvenated team that has rediscovered the thrill of dynamic collective inter-play when highlighted with flashes of individual world-class brilliance. He knows that the 29 year wait endured by Liverpool could be horribly extended by the wrong result on Sunday in a match that has the potential to be one of the great defining games in the history of both clubs.
Liverpool's nil-all draw against Bayern Munich on Tuesday may be just the right result to help them focus on the Man United threat.
"We kept everything tight at the back," said Klopp. "But we made life difficult for ourselves with those final passes. We can play better and we should play better."
While acknowledging that Man United "are obviously in good shape," the Liverpool manager will expect his team to score.
While this match has the potential to derail Liverpool's title hopes and edge Solskjaer closer to a full-time job, no one, least of all Klopp and United's caretaker manager, is expecting this tie to be a damp squib.