Carlo Ancelotti's much-changed Napoli kept the pace on leaders Juventus thanks to a stoppage time free-kick from Arkadiusz Milik.
Having left out the likes of star men Marek Hamsik, Lorenzo Insigne and Dries Mertens, the Polish striker fired in the winner in a largely frustrating encounter dominated by the away side.
In an even first half, Adam Ounas's effort was comfortably saved by home keeper Alessio Cragno, before both Diego Farias and Paolo Farago were denied by David Ospina.
Napoli stepped up the tempo in the second-half and could have had three or four if it wasn't for their wasteful finishing, as Piotr Zeilinski and Milik were found guilty.