It was a subdued start from both sides, although Inter hoarded the early possession as they looked to keep the tempo slow on the wet San Siro turf.
Chances didn’t come easily, and nearly half an hour had gone before David de Gea was troubled, but the Spaniard did well when called upon, preventing Alessandro Bastoni from slotting in after a darting run through the middle.
Inter were spurred on to more chances from there, and Federico Dimarco was left unsure as to how De Gea had adjusted to toe away his effort from the centre of the area.
Other than a half chance for Moise Kean which was easily kept out by Yann Sommer, Fiorentina looked out of ideas in the first half, and things didn’t really improve in the second.
Dimarco instead went close for Inter, before Denzel Dumfries’ close-range volley was somehow batted away by De Gea.
The former Manchester United stopper then tipped over Yann Bisseck’s effort, keeping his side on level terms until the hour mark.
But even he could do nothing about Inter’s opener, which came shortly after when Hakan Calhanoglu shifted it onto his right and buried his shot into the bottom corner from 25 yards out.
The relief was clear to see on Inter faces, and Petar Sucic took it upon himself to double their advantage, shrugging off Rolando Mandragora before entering the box, evading more challenges and finding the inside of the near post.
Any glimmer of hope that Fiorentina had of replicating their 2-2 draw with Bologna last time out was extinguished late on when Mattia Viti took down Ange-Yoan Bonny in the area, resulting in both a second yellow and a penalty.
Calhanoglu dispatched from the spot, keeping his side snapping at the heels of league-leading Napoli and Roma.
Having finished in the European places in each of the last four seasons, things are starting to look worrying for Stefano Pioli’s Fiorentina, who have now recorded their worst-ever start to a Serie A campaign.
Flashscore Man of the Match: Hakan Calhanoglu (Inter)
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