Paulo Sousaâs men grabbed all their goals in the first half, comfortably dominating the newly-promoted minnows at the Stadio Artemio Franchi.
The Portuguese coach opted to make several changes to his starting XI, resting leading scorer Nikola Kalinic in order to allow Mati Fernandez to play behind Khouma Babacar.
Frosinone handed goalkeeper Massimo Zappino his top flight debut, and the Viola would ensure he was heavily involved in the action.
Yet after making an early save from Babacar, the 34-year-old was unable to prevent a cross from Ante Rebic bouncing in off the frame of his goal following a deflection.
If there was some fortune to Fiorentina's opener, there was little doubt of the quality of the second as Gonzalo Rodriguez netted with a sublime back-heeled effort.
Babacar would get on the scoresheet with a chipped penalty before Mario Suarez stole the ball and slotted past Zappino with ease.
After the break, Fiorentina understandably eased the pressure on their mismatched opponents, eventually allowing Frosinone midfielder Alessandro Frara a late consolation goal.
On Saturday Inter downed 10-man Roma 1-0.