After Inter stormed to a two-goal lead in their Champions League semi-final clash, the fifth and final Derby della Madonnina of the season will decide whether it will be the Nerazzurri or Rossoneri half of Italy's second city that journeys on to next month's final.
Match preview
Peaking at precisely the right time, after a season littered with Serie A shortcomings, Inter put one foot in the Champions League final by battering their old foes during a whirlwind first-half display last Wednesday, when Edin Dzeko and Henrikh Mkhitaryan turned back the clock to give the Nerazzurri a dream start.
The ex-Roma pair both struck within 11 minutes of the first whistle, and the first Milan derby to be held in Europe's top club competition for 18 years was always going Inter's way thereafter: Simone Inzaghi's side have now beaten their Rossoneri rivals three time this season, following earlier wins in the league and the Supercoppa Italiana.
Remaining resilient throughout their run to this stage of the competition - in stark contrast to a record of 11 league defeats so far this season - Inter have yet to trail at any point in the knockout stages, keeping a clean sheet in four of five games.
Now on the precipice of a sixth European Cup or Champions League final - the club's first since 2010 - the Nerazzurri are within 90 minutes of taking their place in this year's showpiece early next month - Manchester City or holders Real Madrid will await in Istanbul if they can hold on to their lead.
The form book suggests that should be well within their compass, as Milan have continued dropping points domestically and now trail Inter by five in the Serie A standings, while Inzaghi's men have strode into top form and will kick off the second leg on the back of a seven-match winning run.
With all their vast experience and the recent resurgence of Romelu Lukaku aiding their cause - the Belgian striker scored twice in Satuday's 4-2 win over Sassuolo - they will surely expect to progress in front of a predominantly blue-and-black crowd at the teams' shared San Siro home.
Heightening their psychological burden ahead of the second leg, Milan have now lost their last three games against Inter without scoring a single goal - despite attempting 31 shots all told.
They have never gone four in a row without finding the net against the Nerazzurri in their history, and such a sequence simply cannot continue if they are to salvage something from the clubs' semi-final tie.
Throughout Champions League history, only one team has lost the first leg of a semi by two or more goals and then went on to go through - Liverpool's incredible comeback against Barcelona in 2019 being the only exception - but that is the task standing ahead of Stefano Pioli's side.
Milan striker Divock Origi memorably scored twice in that game, but he was once more unable to find the net on Saturday evening, as the Rossoneri's recent downturn continued with a dismal 2-0 defeat at Spezia.
The thinness of Pioli's squad was exposed again at Stadio Picco, as a much-changed side hampered by a fresh batch of injuries were humbled by the Serie A strugglers; leaving Milan four points adrift of Italy's top four with just three games to play.
After deposing Inter as Italian champions last year, they have recently had to hand over the Scudetto to Champions League quarter-final victims Napoli, and hopes of a first European title since 2007 hang by the slimmest of threads heading into another clash of Calcio kings.
Inter Milan Champions League form:
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Inter Milan form (all competitions):
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AC Milan Champions League form:
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AC Milan form (all competitions):
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Team News
Having made a number of changes at the weekend - to preserve his star men for Tuesday's defining derby - Inter coach Simone Inzaghi will recall players including Lautaro Martinez, Denzel Dumfries and Andre Onana against Milan.
Due to Robin Gosens having just returned to fitness following a dislocated shoulder, Federico Dimarco was retained for the win over Sassuolo, and the wing-back has assisted five goals from open play in the Champions League this season - more than any other player.
Only Milan Skriniar will definitely miss out due to injury, though Joaquin Correa picked up a knock on Saturday and may be sidelined. In any case, the Argentinian striker must make way for Martinez, while it remains to be seen whether Inzaghi will select Edin Dzeko or Romelu Lukaku as the latter's partner up front.
Milan, meanwhile, are dealing with a potentially lengthy absence list, as Junior Messias, Rade Krunic and Ismael Bennacer - whose season has now been ended by a knee injury - all joined star man Rafael Leao in missing the trip to La Spezia.
As the Rossoneri's hopes of reaching the final could hinge on Leao's availability in midweek, the Portugal international will be given every chance to recover; Alexis Saelemaekers is likely to deputise if he fails to pass a fitness test.
Olivier Giroud returns in attack, meaning demotion to the bench for Divock Origi, while captain Davide Calabria should come in for Pierre Kalulu at right-back.
Inter Milan possible starting lineup:
Onana; Darmian, Acerbi, Bastoni; Dumfries, Barella, Calhanoglu, Mkhitaryan, Dimarco; Martinez, Dzeko
AC Milan possible starting lineup:
Maignan; Calabria, Tomori, Kjaer, Hernandez; Tonali, Pobega; Diaz, Krunic, Saelemaekers; Giroud