A dramatic late recovery in Florence saw Vincenzo Italiano's team through to the Europa Conference League semi-finals, and though defeat on the night ended an eight-match unbeaten streak they now travel to Lombardy on a high.
Match preview
Leading 4-1 from last week's first leg, Fiorentina surely felt they had one foot in the Conference League semis as Lech Poznan arrived at Stadio Artemio Franchi on Thursday, but when they trailed by three goals shortly after the hour mark, dreams of European glory were disintegrating in front of their eyes.
Then bound for extra time - or worse still, a humiliating exit - the day was saved by goals from Riccardo Sottil and Gaetano Castrovilli, which ultimately helped the Tuscan side through via a 6-4 aggregate victory.
They will next face Basel in the last four, but thoughts must quickly return to domestic matters, as consolidating a top-half finish in Serie A and confirming a place in the Coppa Italia final are both on the agenda over the coming days.
Last week's 1-1 draw with Atalanta saw an Arthur Cabral spot-kick secure another point towards the Viola's league total, and they have recently recorded 11 wins and three draws from 15 games across all competitions.
Vincenzo Italiano's side have also won their last three away matches in Serie A without conceding - equalling the club's best such run for a decade - and they can now claim a slice of history by posting four straight shut-outs on the road for the very first time.
Despite being held to a 1-1 draw by Monza in January's reverse fixture, when Cabral was on target again, Fiorentina have won seven of their 11 previous meetings with the Lombardy club and will aim to extend that trend on Sunday.
Set to host Fiorentina in a league fixture for the first time since May 1994, Monza will prepare for the Tuscans' visit in confidence that they can close the gap between the teams to a single point with a win.
Only four points behind their opponents in 13th place, Raffaele Palladino's men had already toppled Juventus twice and held Inter on home soil before they reconvened with the latter in Milan, and an unlikely goalscorer brought them an 11th league victory since securing promotion.
Compounding Inter's miserable run in domestic competition, veteran defender Luca Caldirola found the net against his former club last week to stun San Siro, and Monza's last 11 goals have now come from 11 different scorers.
Such a wide array of attacking threat has helped the Biancorossi post 38 points so far, and since the 1990s only two other Serie A debutants have bettered that tally at this stage of their first top-tier campaign - Reggina in 1999-2000 and the now-defunct Chievo Verona two years later.
Rookie coach Palladino - who took charge six months ago, following a slow start to the season - now seeks three successive wins for the first time since October, which was also the last time Monza kept back-to-back clean sheets.
Monza Serie A form:
W
D
D
L
D
W
Fiorentina Serie A form:
W
W
W
W
D
D
Fiorentina form (all competitions):
W
W
D
W
D
L
Team News
Coming through such an intense game on Thursday could see Vincenzo Italiano make several changes to his Fiorentina team this weekend, with South American duo Lucas Martinez Quarta and Arthur Cabral heading the queue for promotion from the bench.
The latter has now scored nine Serie A goals since joining the Viola and seeks to become the fifth Brazilian in club history to reach double figures; the last man to do so was Edmundo, back in 1999.
While Sofyan Amrabat (back) and Josip Brekalo (head) remain minor doubts due to injury - and reserve goalkeeper Salvatore Sirigu has been ruled out for the rest of the season - Italiano has an otherwise full squad to choose from.
Monza, meanwhile, could name an almost unchanged XI as Raffaele Palladino opts for continuity; perhaps his only switch of personnel could come in midfield.
After picking up a thigh injury against his parent club last week, Inter loanee Stefano Sensi is set to miss out, so either Jose Machin or Gianluca Caprari should return to the hosts' lineup.
Elsewhere, roving wing-back Carlos Augusto - a goalscorer in the reverse fixture - starts on the left flank, having made 27 successful dribbles and racked up 29 attempted shots in Serie A this season. Furthermore, the Brazilian also has five goals and as many assists to his name thus far.
Monza possible starting lineup:
Di Gregorio; Izzo, Mari, Caldirola; Ciurria, Pessina, Rovella, Augusto; Colpani, Caprari; Mota
Fiorentina possible starting lineup:
Terracciano; Dodo, Martinez Quarta, Igor, Biraghi; Bonaventura, Mandragora; Gonzalez, Barak, Saponara; Cabral