For any other team in England, tonight's task - beat Liverpool by four goals - would be almost impossible. But Manchester City are one of the most frightening attacking sides in Premier League history and, having beat Jurgen Klopp's team 5-0 earlier in the season, will be confident they can cause a major upset.
City are priced at 9/2 to qualify and 1/2 to win on the night. It might just be worth backing both.
Pep Guardiola made glaring tactical errors in the first leg. His decision to use Aymeric Laporte as an immobile left-back backfired spectacularly, but this was nowhere near his worst decision. Without Raheem Sterling on the right to pin back Andrew Robertson the Scottish left-back ran riot; Ilkay Gundogan had no idea what he was doing on the right; and fielding Kevin de Bruyne in a deeper midfield role meant City didn't have their usual forward pass outlet in the half-spaces. Consequently they were disjointed and resoundingly beaten.
With City set to return to their usual system, the pattern of tonight's contest should be very different. Here are four tactical ways in which the hosts can overturn their deficit:
Silva & De Bruyne can help Sane isolate Alexander-Arnold
The most important aspect of Guardiola's system is the use of dual number tens who, yo-yoing in the half-spaces, allow City to circulate the ball through the middle of the pitch. On home soil this should gradually force Liverpool into deeper positions and see the hosts hold the majority of possession, while crucially sucking the pitch inwards.
Liverpool will get narrower and narrower as they try to squeeze the space in which De Bruyne and Silva operate - falling into the trap Guardiola is setting for them. As the game narrows, Leroy Sane will stand wide on the left flank, awaiting a diagonal pass that suddenly shakes up the rhythm of the attack.
When this happens, Sane will find it much easier to isolate Trent Alexander-Arnold and skin the young right-back. He was unable to do this in the first leg because of City's overall lack of fluidity, and while Alexander-Arnold was outstanding at Anfield he is faced with a considerably tougher challenge this time.
Sterling's arcing runs could negate Liverpool's hard-tackling midfielders
Raheem Sterling is likely to start on the right wing tonight, which is bad news for Liverpool for a couple of reasons. Firstly, the England international will either pin back Robertson or expose his high starting position, and secondly Sterling's arcing runs on the shoulder of the last defender offer City an alternative route to goal.
Jordan Henderson's absence through suspension is a huge hit for Liverpool (De Bruyne and Silva are likely to have more joy through the centre). But even if James Milner - who amassed five tackles and three interceptions at Anfield - dominates the midfield battle again City now have alternative options.
As Sterling moves into pockets around Virgil van Dijk, Silva and De Bruyne will have more direct passing options that allows them to steer clear of another gritty midfield battle.
Aguero's new link-up abilities might grind Liverpool down
Sergio Aguero is likely to start upfront after Guardiola confirmed the striker only missed out against United because they didn't want to "take a risk". On current form, the Argentine is a big upgrade on Gabriel Jesus - and should further help City gain control of the ball, defining the rhythms of the match.
Over the last two months Aguero has begun to drop off at the right moments, linking play with neat one-touch football that defies suggestions he cannot adapt to the Guardiola system. All of a sudden the 29-year-old looks like the ideal striker for Pep - and that's bad news for a Liverpool side without a recognisable defensive midfielder.
Georginio Wijnaldum will probably come in for Henderson, but the Dutchman isn't positionally adept. Liverpool's centre-backs cannot afford to push up onto Aguero, and yet their midfielders instinctively don't want to drop into an anchor position; the City number 10 could be the catalyst for a dramatic comeback.
More aggressive right flank, and Delph deep on the left, can stop Liverpool's wide attacks
Laporte struggled to keep close to Mohamed Salah last week, which should mean Fabian Delph returns to the role tonight. He plays primarily as an inverted left back, helping to control central midfield but also sticking touch tight to opposition inside forwards. Delph will be better than Laporte was at blocking Salah's runs.
On the other flank, Sterling's threat should limit Robertson's ability to drive forward. There is still a big question mark over Kyle Walker - his attacking instincts could leave his side vulnerable to Sadio Mane on the counter - but overall City should be much more stable defending the flanks this time around.