Proceedings restarted with a Fiorentina throw-in in the 17th minute, but it was Inter who settled quicker into their rhythm - forcing David de Gea into a decent save to keep out Lautaro Martinez before the goalkeeper was aided by Luca Ranieri, who made an important block to deny Alessandro Bastoni.
The visitors thought they had a deserved breakthrough on the 30-minute mark when Bastoni hooked a half-cleared corner back into the penalty area, which Carlos Augusto tucked home only for VAR to rule his goal out for offside.
That was the wake-up call La Viola needed, and three minutes later Fabiano Parisi curled a cross right onto Moise Kean’s forehead, yet somehow Yann Sommer got something behind the striker’s header.
Kean then turned provider to send Dodo bearing down on goal, only for him to drag his shot wide with only Sommer to beat.
Raffaele Palladino’s men finally increased their accuracy in front of goal on the hour mark, when a Rolando Mandragora corner was swept into the bottom corner on the volley by Ranieri for his first league goal of the season.
Ranieri was back on defensive duty moments later with another block, this time denying Martinez.
That looked all the more crucial five minutes on when Dodo picked out Kean with a cross to the back post, and this time the striker buried his header beyond Sommer and into the bottom corner to double the lead.
A hopeful Nicolo Barella effort from long-range and Marko Arnautovic failing to stab home from six yards was all Simone Inzaghi’s side could muster late on.
A first three-point haul over Inter at Stadio Artemio Franchi since 2017 was wrapped up one minute from time when Kean pounced on a poor backpass and slotted the ball past Sommer, who was hopelessly out of position.
Fiorentina are now unbeaten in four matches, while a first league loss since September means Inter missed the chance to go top of the table on goal difference.