Raffaele Palladino's side are on a high and level on 28 points with champions Inter, with the two teams among a group of four trailing leaders Napoli by a single point.
Both will know by kick-off whether they can overtake Napoli who are at Torino just before the weekend's big match at the Stadio Artemio Franchi.
But just being in the mix at this stage of the season is huge for Fiorentina who under new boss Palladino have found a winning formula and, above all, a resilience that was missing with his predecessor Vincenzo Italiano.
Last weekend's 2-0 win at Como came thanks to a grinding performance and more goalkeeping heroics from David de Gea, who has grabbed with both hands his opportunity in Florence after a year as a free agent.
"I don't like winning this way but it gives you an idea of what the boys are worth... They're motivated and competitive," said Palladino after the win at Como.
"They don't want to lose and they want to give it a go with everyone."
Fiorentina, whose last major trophy was the 2001 Italian Cup, face an Inter team who are not hitting the heights of last season's charge to the Scudetto but still riding high.
Tuesday's routine 1-0 win over Leipzig moved Inter top of the Champions League and to the brink of qualification for the last 16, giving coach Simone Inzaghi more room to concentrate on his team's title defence.
Inzaghi will have to do without starting defenders Francesco Acerbi and Benjamin Pavard, the latter of whom was forced off the field just before half-time on Tuesday with a left thigh injury.
Ready to pounce on any slip-ups are Atalanta, who are continuing to enchant with some of Europe's most exciting football and face struggling Roma in Rome on Monday night with coach Gian Piero Gasperini suspended following a tirade against officials last weekend.
Gasperini's side are another of the teams on Napoli's tail and cannot be discounted from the title tussle after winning 10 in 11 matches in an unbeaten run which stretches back to the start of October.
Atalanta were again at their joyous best on Tuesday when they destroyed Young Boys 6-1, with Charles De Ketelaere and Mateo Retegui again the stars of the show, turning on the style even without Ademola Lookman.
"The truth is that we have a team that has so much quality and experience. We're playing beautiful football," said Retegui to Sky.
"We're playing as well in Europe as we are in Italy and we have to keep it up, not let up, work hard and keep our feet on the ground."
Lazio, the last of the chasing group of four and on a seven-match winning streak of their own, are at Parma at the same time as Napoli face Torino.
Player to watch: Moise Kean
Seven goals in his last four matches makes Italy forward Kean the form striker in Serie A, and Sunday's match will also be a barometer for just how far the 24-year-old has come since moving to Fiorentina from Juventus.
Kean has scored 12 times in all competitions so far this season and is already approaching his best-ever season tally of 17 goals, which he hit at Paris Saint-Germain four seasons ago.
He will also benefit from the likely return of summer signing Albert Gudmundsson after over a month out with a hamstring injury.
Key stats
4 - The number of teams one point behind Napoli.
7 - Atalanta and Lazio's all-competition winning streak, while Fiorentina have the same number of consecutive wins in Serie A.
Fixtures (times GMT)
Friday
Cagliari v Verona (1945)
Saturday
Como v Monza (1400), AC Milan v Empoli (1700), Bologna v Venezia (1945)
Sunday
Udinese v Genoa (1130), Parma v Lazio, Torino v Napoli (1400), Fiorentina v Inter Milan (1700), Lecce v Juventus (1945)
Monday
Roma v Atalanta (1945)
