Napoli have held off a strong second-half effort from Fiorentina to claim a 2-1 victory in Tuscany, courtesy of early strikes from Jose Callejon and Dries Mertens.
La Viola started brightly but were caught cold on 11 minutes by a ruthless Napoli counter, which saw Gonzalo Higuain pick out Callejon with a clever diagonal pass.
The Spaniard made no mistake to break the deadlock, measuring a controlled volley into the far corner.
Napoli sat deep and looked dangerous on the counter, but were pegged back on 28 minutes as the hosts were awarded a spot kick following Federico Fernandez's push on Stefan Savic.
Giuseppe Rossi stepped up and confidently sent Pepe Reina the wrong way, drawing La Viola level despite fierce protests from the visitors with his ninth goal in 10 league games.
Juan Cuadrado struck the post in the very next attack as Fiorentina seized control of possession and territory, but Napoli were able to hit on the counter to go ahead just before the break.
Belgian international Mertens did the damage on the break, beating three players to drive inside the penalty area and smash his first Napoli goal into the bottom corner.
When play resumed after the interval Fiorentina once again dictated play, but had two penalty appeals turned down as Cuadrado and Rossi were both booked for simulation.
Rossi then forced Reina into a smart stop as his shot was diverted on its way towards the top corner, with Napoli sending on Marek Hamsik and Lorenzo Insigne for fresh legs in attack.
Ten minutes from time Napoli had a man sent off as Christian Maggio picked up his second booking, but Rafael Benitez's side held firm for a victory which sees them stay second in Serie A.
In stoppage time the referee issued another red card in controversial circumstances after Cuadrado went down under a trip in the box from Gokhan Inler, only to receive a second yellow card as La Viola lost their unbeaten home record.
