When: Thursday, May 13, 20:15 BST
How to watch: Sky Sports Main Event
It's hard to believe the turnaround from last season if you're a Liverpool fan.
The Merseysiders finished 33 points ahead of Manchester United as they powered to the title; going into this one, they're 13 points behind their great rivals from down the East Lancs Road.
What's more, this is a fixture that the Mancunians dominate. In the last 15 meetings at Old Trafford, it's 10 wins for United, four draws and just a single victory for Liverpool.
If Liverpool feel a bit cursed this season, the rearranging of this match following the fan protest at Old Trafford two Sundays ago only adds to it.
With United having to play three Premier League games in five days, it means Ole Gunnar Solskjaer sent out a weakened team against Leicester on Tuesday night.
Leicester also had a poor record at Old Trafford but did enough to beat a makeshift United and hammer a nail in Liverpool's Champions League hopes.
Some Reds fans cried foul but others held their hands up, admitting that Solskjaer had every right to do it and that Liverpool wouldn't be in such a position had they played better this season.
Tuesday's defeat handed the title to Manchester City but that was always going to be the case.
United have a Champions League spot wrapped up, a Europa League final to look forward to and some rested players to unleash on Liverpool.
Last three meetings:
Man Utd 3-2 Liverpool (January 24, 2021)
A week after they'd played out a 0-0 stalemate in the league at Anfield (see below), this FA Cup clash was a far more entertaining encounter.
Salah levelled just before the hour mark with his second of the game but the hosts struck the decisive blow when second-half substitute Bruno Fernandes blasted home an excellent 78th-minute free-kick to send United through. Both teams had 14 shots overall and six each on target.
Liverpool 0-0 Man Utd (January 17, 2021)
Before they went on a horror run of six straight home losses, Liverpool played out a drab 0-0 draw with United at Anfield.
Given what was to come, the visitors would see this as a missed opportunity and, indeed, Ole Gunnar Solksjaer used that phrase post-match after watching his side carve out the better opportunities.
Liverpool 2-0 Man Utd (January 19, 2020)
Wind back a year from that 0-0 and this was Liverpool in their pomp: steamrollering everyone before them and charging towards the title.
Virgil van Dijk headed them into a 14th-minute lead and, after facing some late United pressure, the Reds wrapped up the victory when Salah coolly slotted home after being sent racing clear by Alisson's long clearance.
That clincher seemed a symbolic moment, sparking joyous scenes as Liverpool's fans really started to believe that this was their year. From here, it just seemed a matter of when not if.
Head-to-head - last 10
Man Utd wins: 2
Liverpool wins: 2
Man Utd scored: 8
Liverpool scored: 10
Liverpool hopes hanging by a thread
Leicester's win at United now leaves Liverpool on the brink in terms of claiming a top four spot.
With their final three games against West Brom (a), Burnley (a) and Crystal Palace (h), there's a good chance of ending the campaign with three wins.
That would take the Reds to 66 points but that's the amount Leicester have already. Chelsea have 64 with three games to play.
If Liverpool lose, Leicester only need a point and Chelsea just three to leave the Merseysiders outside the top four.
A draw also leaves Jurgen Klopp's men looking down the barrel.
In short, Liverpool really have to win all four of their remaining fixtures.
Liverpool's last five results:
Liverpool 2-1 Aston Villa (Salah, Alexander-Arnold)
Liverpool 0-0 Real Madrid
Leeds 1-1 Liverpool (Mane)
Liverpool 1-1 Newcastle (Salah)
Liverpool 2-0 Southampton (Mane, Thiago)
Scoreline prediction: Man Utd 2-1 Liverpool
As stated, United have a superb record against Liverpool at Old Trafford.
However, the odds seem to be ignoring that and putting more emphasis on motivation: Liverpool virtually have to win while United do not.
But let's be honest, it doesn't take a genius to work out why United sent out a second-string side against Leicester rather than Liverpool.
Solskjaer and just about everyone at United would love to put one over last season's champions and deliver a killer blow to the visitors' top four hopes.
Klopp has never won at Old Trafford in six attempts and I don't see that changing.
The hosts are value for the win at 19/10 and it's also worth having a punt on United's favourite trick of coming from behind after a poor start.
It's a massive 25/1 that Liverpool lead at half-time but United hit back in the second half to win. Snap it up.
Best Goalscorer bets
After being rested from the starting XI against Leicester (he came on for the last 24 minutes), Edinson Cavani could be given the nod for this one.
And, if so, the Uruguayan is in superb goalscoring form after netting eight in his last eight.
Liverpool are still conceding goals so Cavani to score anytime at 15/8 looks worth a punt.
For the visitors, Salah remains their only reliable scorer and is available at a best 11/8 with Unibet.