Holders Napoli seek to take another step towards retaining the trophy, while the hosts bid to keep alive their dream of a first cup triumph in nearly 60 years.
Both sides vying to meet either Inter Milan or Juventus in May's Coppa Italia final endured unsatisfactory outcomes at the weekend, in Serie A encounters they were hotly tipped to win.
Atalanta seemed to have their home game against Torino well under control after going 3-0 up before the half-hour mark, as goals from Josip Ilicic, Robin Gosens and Luis Muriel put them into an apparently unassailable lead. However, a Toro side transformed under new coach Davide Nicola then salvaged a third consecutive comeback draw, with Federico Bonazzoli's late header ultimately completing their revival.
After such a deflating result, La Dea must quickly get back on their feet for the second of three meetings with their Neapolitan counterparts this month - with this two-legged cup tie soon to be followed by a Serie A fixture.
Parts two and three of the trilogy could prove critically important to the Bergamaschi's hopes of turning their abundant promise and inherent 'watchability' into something more solid and silver this season.
The first leg of the semi-final may have ended 0-0 at Stadio Diego Maradona, but Atalanta had the best scoring opportunities, forcing several saves from Napoli goalkeeper David Ospina.
Despite missing out on the opportunity to take away a precious away goal advantage, Gian Piero Gasperini's team will still start as favourites on Wednesday, but can expect another testing tussle with the Partenopei, who they are locked with on 37 points in the Serie A standings - albeit having played a game more.
If Atalanta were downhearted at the final whistle last weekend, then Napoli were downright desolate after their loss to a rapidly improving Genoa side at Stadio Luigi Ferraris.
Veteran forward Goran Pandev's double against his former club, allied to Mattia Perin's ongoing excellence in goal saw Gennaro Gattuso's men slip to a 2-1 defeat, in which they struck the woodwork twice - from Andrea Petagna's header and a Lorenzo Insigne volley. Though Matteo Politano fired in late on for the visitors, it proved too little, too late and any lingering hopes of a Scudetto challenge have now been extinguished.
The continuing battle between Gattuso and club president Aurelio De Laurentiis surely only has one 'winner', after Napoli's temperamental custodian was reportedly furious after their latest defeat. The two upcoming games against Atalanta - followed by a crunch clash with Juventus - are apparently set to be decisive for the future of his similarly tempestuous coach, as candidates such as Rafa Benitez and Max Allegri wait in the wings.
Defensive mainstay Kalidou Koulibaly scored the opening goal in the previous round and spoke out in support of his manager before last week's opening leg, claiming that this current Napoli unit are one of the best in which he has featured so far. However, the Senegalese star will be sorely missed by his boss on Wednesday, having tested positive for COVID-19 in the intervening period.
Gattuso took the radical step of switching to a back three, helmed by Koulibaly, to combat Atalanta's fluent attack in the first leg - the first time he has done so since taking charge in 2019. The embattled former Milan manager may have to come up with another tactical masterstroke upon his return to Lombardy this week, if he is to keep his side on course for back-to-back Coppa Italia triumphs.
Napoli's last trip to the Gewiss Stadium came last July, ending in a 2-0 defeat, while the clubs' first league encounter of the season ended 4-1 to the Nerazzurri in Naples. A score draw would be enough for the Partenopei to progress this week though, so writing them off entirely would be reckless.
Atalanta BC Coppa Italia form: WWD
Atalanta BC form (all competitions): DWWLDD
Napoli Coppa Italia form: WWD
Napoli form (all competitions): LLWWDL
Atalanta have a dilemma to solve regarding their influential wing-back position, as both Joakim Maehle and Hans Hateboer are set to miss out on Wednesday. Centre-back Rafael Toloi adapted to a role on the right in the second half against Torino and could continue to cover. If not, young Bosko Sutalo would come in.
Recently returned from injury, Mario Pasalic is a candidate to play in support of striker Duvan Zapata, or Luis Muriel could instead be offered the chance to join his Colombian compatriot in a front two.
Visiting coach Gennaro Gattuso is not expected to retain the three-man back line he employed in Naples, particularly as Kalidou Koulibaly is absent due to COVID-19. Back-up defensive pair Amir Rrahmani and Nikola Maksimovic must instead step up to the plate, given that Kostas Manolas is also out of action until the end of the month.
Tiemoue Bakayoko is likely to be teamed with Piotr Zielinski and Eljif Elmas in midfield, while it remains to be seen whether Gattuso will opt for a diminutive front trio or introduce Victor Osimhen as a more typical 'number nine'.
Atalanta BC possible starting lineup:
Gollini; Toloi, Palomino, Djimsiti; Sutalo, De Roon, Freuler, Gosens; Pessina; Muriel, Zapata
Napoli possible starting lineup:
Ospina; Di Lorenzo, Maksimovic, Rrahmani, Hysaj; Elmas, Bakayoko, Zielinski; Lozano, Osimhen, Insigne
We say: Atalanta BC 2-1 Napoli
Despite facing the jeopardy of conceding a potentially fatal away goal, Atalanta can exploit Napoli's defensive absences with their characteristic verve and clinical finishing.
Undermined by the respected Koulibaly-Manolas pairing missing out and their recent inconsistency, the cup holders could bow out at the semi-final stage, leaving La Dea to dream on until May.