Vincenzo Montella's men have experienced a wobble at precisely the wrong time in recent weeks, going four Serie A matches without a win until Sunday's 3-1 home success over Chievo stopped the rot.
That poor run has seen them drop 10 points behind Napoli, who currently occupy the third and final Champions League qualification berth.
With 10 games remaining, Fiorentina know anything other than maximum points in Naples on Sunday will surely leave them with too much to do to break into the top three.
It will be no easy task though, as they face a Napoli outfit that has lost just one home match in the league this season - that coming in November when Parma edged them 1-0.
Since that defeat, Napoli have lost just once in 15 Serie A matches, a surprise 3-0 beating at the hands of Atalanta last month.
The Naples outfit are in equally desperate need of the points as they look to close the three-point gap to the second-placed Roma, who sit in an automatic Champions League spot.
Roma could be six points clear by the time Napoli play, though, as they travel to Chievo 24 hours earlier.
Elsewhere in the race for European football, fifth-placed Inter host Atalanta while Parma, a point and a place below Walter Mazzarri's side, welcome Genoa.
Parma are unbeaten in 16 league fixtures and won 4-2 at Milan on Sunday.
Milan, who have now lost four matches in a row in all competitions, go to the seventh-placed Lazio in search of a much-needed win.
Fan protests preceded Sunday's defeat and pressure is building on manager Clarence Seedorf, who replaced Massimiliano Allegri in January.
At the wrong end of the table, bottom club Catania have the daunting task of taking on runaway leaders Juventus at Stadio Angelo Massimino while Sassuolo, who climbed off the bottom after beating Catania last week, visit Udinese.
Livorno got the better of fellow strugglers Bologna last week and they will be hoping to take that winning momentum into their trip to Torino, and Davide Ballardini's men need to bounce back when they take on Cagliari at home.
Elsewhere, Sinisa Mihajlovic was scathing in his assessment of his Sampdoria players following last week's loss at Atalanta, and he will demand a response when they welcome Verona.
