Goals from Matteo Darmian, Edin Dzeko and Ivan Perisic sealed another three points for Simone Inzaghi's side and they now sit at the top of the table.
It was certainly a tough outing for the Italian champions, though.
Fiorentina took the lead in the first half through Riccardo Sottil and it took until the 52nd-minute for Inter to respond through Darmian.
Dzeko put the visitors 2-1 up three minutes later and then the game was effectively over as a spectacle when the home side were reduced to 10-men in the 78th-minute.
Nicolas Gonzalez was the man dismissed from the field of the player and the way in which he picked up his red card was like something out of a comedy sketch.
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The Argentine winger was fouled and then gestured to the referee that the Inter player be booked as a consequence.
The official didn't agree and instead yellow carded Gonzalez, which prompted the 23-year-old to sarcastically clap in the official's direction.
Unsurprisingly, that resulted in a second booking and saw him sent off.
But despite the fact he'd been red carded, Gonzalez continued to antagonise the referee and eventually had to be held back by Inter's Hakan Calhanoglu.
Take a look at footage of the Fiorentina man losing his head here...
Video: Gonzalez's meltdown vs Inter
That's without question one of the stupidest red cards we've ever seen handed to a player in one of Europe's top five leagues.
What makes it worse is that up until that point, Gonzalez was having a pretty good game and could potentially have salvaged a point for Fiorentina in the final 10 minutes if he'd remained on the field.
Nine minutes after the avoidable sending off, Perisic made it 3-1 to Inter and ended any hopes of a dramatic comeback by the hosts.
Gonzalez will now miss Fiorentina's trip to Udinese on the weekend and it remains to be seen whether he will receive any further punishment for his actions on Tuesday.