Fiorentina came back from 2-0 down and again to equalise in the final minute with Luka Jovic’s acrobatic volley, but a bizarre Henrikh Mkhitaryan goal deep into stoppages sealed Inter’s 4-3 victory amid refereeing controversy.
Inter were a goal ahead after 90 seconds through Nicolo Barella, before Martinez doubled the visitor’s lead after 15 minutes.
Fiorentina pulled a goal back from the penalty spot through Arthur Cabral, before Jonathan Ikone completed the comeback with a sublime curled finish into the top corner on the hour mark.
Inter were awarded a penalty of their own when Martinez was brought down by goalkeeper Pietro Terracciano with a little over 15 minutes to go, and the Argentine fired his side back into the lead.
Fiorentina continued to push for an equaliser, and finally their persistence paid off as substitute Luka Jovic fired in a last-minute equaliser from close-range.
The action wasn’t finished there though as Henrikh Mkhitaryan rode deep into added time to get in the way of a Nikola Milenkovic clearance inside the Fiorentina box, and divert the ball into the bottom corner to steal all three points.