The Partenopei were still missing Victor Osimhen, with Dries Mertens back on the bench after a month, but Fabian Ruiz tested positive for COVID-19. Jose Callejon returned to Naples for the first time as an opponent, with Franck Ribery also fully fit again after injury.
Napoli took the lead with their first foray forward, as Chucky Lozano burst down the right, pulled back from the by-line and Andrea Petagna laid it off for Lorenzo Insigne to score from 12 yards.
Lozano almost did it again moments later, his back-heel flick for Petagna intercepted at the last moment, but Fiorentina came so close to equalising with an own goal on 23 minutes. Cristiano Biraghi’s scuffed volley took a big deflection off Diego Demme, looped over David Ospina and bounced off the crossbar.
Ospina had to get down for a sensational one-handed reaction save on Ribery after Demme was caught in possession, then was glad to see Biraghi’s angled drive skim the far post.
However, Napoli doubled their lead with a classic counter-attack. Piotr Zielinski won it back in midfield, spread the play for Petagna, who provided his second assist of the game, rolling across for Demme to come sliding in from 10 yards.
Fiorentina did most of the attacking, but the Partenopei were absolutely clinical. Insigne created the third goal out of nothing, starting the run from his own half, drawing three defenders towards him, then sending Lozano to the back post with an absolutely inspired slide-rule pass.
The first half wasn’t even over yet, because Zielinski gathered in midfield, sent Gaetano Castrovilli to ground with a shimmy and placed a snooker-shot in off the inside of the near post from the edge of the box for 4-0.
Insigne was very harshly booked for simulation when he ran into Nikola Milenkovic’s leg, as though it wasn’t a penalty, it certainly was not a dive either.
Fiorentina’s luck really wasn’t in, as Dusan Vlahovic dinked his finish over Ospina only to be denied by a Kalidou Koulibaly goal-line clearance.
Insigne saw his right-foot curler well saved by Bartlomiej Dragowski, but as Tiemoue Bakayoko got on the rebound, he was tripped by Gaetano Castrovilli. Insigne stepped up and converted the penalty for his brace, even if Dragowski did get a glove to it.
Matteo Politano came off the bench and got some glory for himself too, dribbling forward to cut inside past defenders and drill into the bottom corner.