If Ole Gunnar Solskjaer has his way at Old Trafford, Liverpool will discover just how far Manchester United have come since these two bitter enemies last met in December.
It has been quite a transformation. From the defeat at Anfield that saw the axe fall on Jose Mourinho to the remarkable resurgence under Solskjaer.
As one United insider told Sportsmail: 'It feels like someone has drawn back the curtains and let the sunshine in.'
The enduring image of Mourinho's last game is Paul Pogba sat on the bench at Anfield, an unused substitute as a United team devoid of ambition sank to a 3-1 defeat against their biggest rivals.
'I'm done after this,' Mourinho confided to friends in a text message as he slipped away that night. 'But I'm not quitting.' He was right on both counts.
His employers had grown tired of the negativity. They never envisaged, though, just how quickly the man installed as caretaker would turn things around. Approaching the 20th anniversary of his famous winner in the Champions League final, Solskjaer is performing another miracle.
United have their mojo back and there has been improvement throughout the team. Pogba looks like a world beater, Marcus Rashford a man possessed. Victor Lindelof, written off as a £30million misfit, has become the bedrock of United's defence.
It is hard to imagine any coach having such an effect on an English club, certainly one the size of United.
No sooner had the black clouds of Mourinho's acid reign blown away than Solskjaer breezed back into Old Trafford in December to bestow bars of his favourite Norwegian chocolate on the female members of staff at Carrington — as he always did during his 14-year career as a player and reserve team manager — and goodwill on the rest of the club.
On his first day back, he accepted an invitation to the staff Christmas party. Typically, Solskjaer turned up in a club suit but had to borrow a jacket left behind by Daley Blind, as he had yet to be measured up for one of his own.
The message to the fans who serenaded him on stage at Lancashire Cricket Club alongside executive vice-chairman Ed Woodward that night was clear. 'It feels like I've come home,' said Solskjaer. 'It's everyone's job to enjoy themselves at United.' The mantra has been repeated many times since.
The 45-year-old has drawn heavily on old school United values and the ethos of his mentor Sir Alex Ferguson. One minute, Solskjaer will be seen at Carrington with his arm around a player offering advice or regaling them with tales of United's Treble season. The next, he is asking after a member of staff's family, having remembered their names from years ago.
Amid the recent baby boom at United, Pogba was allowed to stay on the team's charter flight back from Newcastle last month so he could travel alone to London to see his pregnant partner Maria Salaues. For the same reason, he joined up late with United's training camp in Dubai, which Solskjaer used to bond with his squad and arranged a night out for all the players and staff at the Play Restaurant.
Everyone is made to feel part of the team. Players left out of a game are told to focus on their role in the next one. Those named among the substitutes are reminded that no one spent more time on the bench than Solskjaer.
It would be wrong to paint the Norwegian as a soft touch, though. Tough decisions have been made to leave out Romelu Lukaku and Alexis Sanchez in favour of a more dynamic attacking trident of Rashford, Anthony Martial and Jesse Lingard.
Even so, Martial was ordered to stay away from the Boxing Day game against Huddersfield after missing a flight back from Paris.
Those who witnessed Solskjaer's reaction to United's performance in the first half of their FA Cup tie against Reading realised he wasn't joking when he claimed in an opening press conference to have 'a hairdryer' of his own.
And in the recent win at Fulham, he summoned Juan Mata to the touchline in the opening 10 minutes and told him to warn Phil Jones to raise his game or he would be replaced.
Always, though, the criticism quickly becomes constructive. Unlike Mourinho, Solskjaer is not one to dwell on negatives.
After last week's Champions League defeat to Paris Saint-Germain, the one blot on his copybook in 13 games so far, the dressing-room door was shut for a quarter of an hour while Solskjaer addressed the players and their shortcomings on the night. As they emerged, one member of staff was heard to say, 'now that's what I call coaching a team'.
Solskjaer is not afraid to listen and learn from others. He was seen scouting the opposition at PSG with one assistant, Mike Phelan, and Manchester City with another, Mark Dempsey.
Michael Carrick and Kieran McKenna, the two English coaches excluded from Mourinho's final staff meeting as he took refuge behind his trusted Portuguese backroom team, are given the lead in training.
When United's bench celebrate a goal — like Rashford's effort from Pogba's assist against Tottenham that was devised in Dubai — the camaraderie is plain to see.
After Solskjaer won the manager of the month award for January, he not only insisted on having his picture taken with the coaching team, but made sure it was the only one distributed by the Premier League.
Ferguson, too, has been a more regular visitor to Carrington. Solskjaer was only half-joking when he suggested letting his old boss give a team talk before the Liverpool game.
While David Moyes, in particular, seemed keen to move away from Ferguson's methods, Solskjaer is happy to turn back the clock.
For instance, players are once again required to wear club suits on matchdays and use the gym before training, which always focuses more on United's strengths than those of their opponents.
The exercise bike installed in the manager's office by Mourinho has disappeared and the door remains permanently open. 'To players, coaching staff, the cleaner, you name it,' said one insider.
Solskjaer has wasted no time vacating the Lowry Hotel that hosted his predecessor for so long. He has moved to an apartment in Cheshire while his wife Silje and their three children live in Norway. Solskjaer is not comfortable being apart from them, but the situation makes sense while his future is up in the air.
If he can mastermind another win over Liverpool, it might become clearer sooner rather than later.