With the destiny of the tie remaining in the balance after an eventful 2-2 draw in the first leg, two of Europe's grandest names go into the decider in wildly contrasting domestic form.
There were two penalties, a sending-off and an own goal to digest in the first leg of this evocative tie at Stadion Rajko Mitic last week, with Milan taking the lead twice before Red Star substitute Milan Pavkov grabbed an added-time equaliser to keep alive his team's hopes of reaching the final 16 for the first time.
Now looking to put aside some serious domestic troubles, which have seen Stefano Pioli's 'winter champions' finally dethroned by city rivals Inter at the top of the Serie A standings, the Rossoneri must host a side in formidable form, boasting a record fit to compete with their own incredible post-lockdown streak last year.
Having maintained top spot for 21 rounds, Milan finally let first place slip due to a shock defeat against Spezia earlier this month - a result which the modest Ligurian side fully merited. Worse was to follow, as upon their return from Belgrade, Pioli's men were outclassed by their ruthless San Siro-sharing cousins in a Derby della Madonnina they will want to immediately forget.
Losing 3-0 to chief Scudetto rivals Inter represents hardly the best preparation for a return to the silverware trail in Europe, so in the aftermath of that humbling loss, Pioli will necessarily make some changes to his usual starting XI against Red Star this time out - particularly with a high-profile encounter versus Roma to tackle this weekend.
Precedent, if not form, is in the Italian giants' favour though, as these clubs have been paired twice previously in UEFA competition, with Milan prevailing on both occasions.
The Rossoneri most infamously met this Thursday's opponents in the second round of the 1988-89 European Cup - a competition which the Serie A side went on to win, before sealing back-to-back successes the following year. After two 1-1 draws - the second of which came a day after the initial second leg had been abandoned because of fog in Belgrade, with the home side leading - Arrigo Sacchi's men scraped through on penalties.
This reborn and rejuvenated Milan, under the careful guidance of Pioli, would settle for something similar this season, to break their alarming downward trajectory and take one step closer to the trophy.
Befitting a team who have overwhelmed all-comers in recent months, Red Star were able to salvage a brave draw in the first leg, despite Milan Rodic's 77th-minute red card.
Even present in reduced numbers due to government restrictions, their notoriously vociferous supporters played a role in such relative 'success', though the club's ultras were implicated in accusations of racist chanting after the game. Unused substitute Zlatan Ibrahimovic was apparently targeted with racist epithets by some fans at the Marakana, with the Serbian club subsequently apologising, and UEFA has now launched an investigation.
Ahead of what is sure to be a hard-fought rematch, albeit without Milan tifosi allowed on this occasion, former Inter legend Dejan Stankovic - who will have particularly enjoyed his weekend scouting mission on television - has established Red Star as a side to respect. With Crvena Zvezda's last defeat in all competitions coming as far back as late October, at the hands of Bundesliga club Hoffenheim, momentum is with the boys from Belgrade.
From there on, a run of 18 wins and four draws has seen Crvena Zvezda dominate domestically, as their tally of 62 points (with a goal average of nearing three per game) has them six ahead of bitter foes Partizan, with a game in hand.
Well set for a 31st national title, the 1991 European champions can continue to dream of an against-the-odds return to continental success in the spring, if they can first pull off a San Siro shocker against stumbling Milan.
AC Milan Europa League form: WLDWWD
AC Milan form (all competitions): LWWLDL
Red Star Belgrade Europa League form: WWWDDD
Red Star Belgrade form (all competitions): WWWWDW
The hosts will make several changes from the derby defeat at the weekend, particularly with one eye on Roma's arrival in the second city this Sunday.
In central midfield, Soualiho Meite is expected to take over from Sandro Tonali, with Ismael Bennacer still out injured, while Pierre Kalulu should come in on the right and Fikayo Tomori in the middle of the Milan defence - Davide Calabria and Simon Kjaer would therefore drop out.
Red Star coach Dejan Stankovic, no stranger to San Siro, will be forced to do without the suspended Milan Rodic, who was sent off in the first leg. As cover, the also aptly-named Milan Gajic could take Rodic's spot on the left.
Winger Aleksandar Katai - the club's top Europa League scorer so far - has been out since December with an adductor injury and remains unavailable, though midfielder Veljko Nikolic, who suffered an ankle knock last week, returned to the squad at the weekend.
Scorer of the late equaliser in Belgrade, Milan Pavkov is in contention to start up front, ahead of Diego Falcinelli.
AC Milan possible starting lineup:
Donnarumma; Kalulu, Tomori, Romagnoli, Hernandez; Meite, Kessie; Castillejo, Krunic, Leao; Rebic
Red Star Belgrade possible starting lineup:
Borjan; Milunovic, Pankov, Degenek; Gobeljic, Kanga, Petrovic, Gajic; Ben Nabouhane, Ivanic; Pavkov
We say: AC Milan 1-0 Red Star Belgrade
A potentially tense duel for a last-16 spot will see Milan make the most of their away goals advantage and keep the in-form Serbian champions in check.
Breathing new life into a stuttering season may be too much to ask from Thursday's appointment at San Siro, but the Rossoneri can at least return to winning ways and stay on track for a least one trophy from what has - until recently - been a stellar campaign.
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