A moment of brilliance by Gonzalo Higuain was enough to see Napoli past a dogged Lazio side, who defended resiliently, yet offered little in attack. The loss is Edy Reja's first since replacing Vladimir Petkovic.
Lazio were ravaged by injuries, forcing Reja to rotate his squad. Stefan Radu, Ederson and Miroslav Klose all missed the trip and first choice goalkeeper Federico Marchetti was still not fully fit. He was on the bench alongside Inter Milan transfer target Hernanes.
Napoli were quick to put their visitors onto the backfoot. Inside the first minute, Etrit Berisha needed to be alert to prevent Marek Hamsik's pullback from finding Lorenzo Insigne in the area. The shot stopper then fisted away an angled drive from Higuain at the near post.
Higuain came off worse from a collision with Michael Ciani, but the forward was able to continue after some treatment on the touchline. The French defender intercepted Jose Callejon's first time ball to deny Higuain a shot at goal. Lazio's Andre Dias needed his shin wrapped after a bizarre coming together with teammate Ciani.
Poor control let Callejon down in the area. The Spaniard shaped to shoot and somehow let the ball overrun. Lazio lost defender Abdoulay Konko to a calf injury on 34 minutes. His replacement, Luis Cavanda fired over after Ogenyi Onazi broke clear. A combination of hesitancy and poor decision making from the Nigerian meant he held onto the ball too long and ignored an irate Keita Balde, who was in a more promising position to test Reina.
Napoli finished the first half strongly. Diego Novaretti robbed Higuain with a last ditch tackle, just as the Argentine was set to pull the trigger from point blank range. Berisha wasn't fazed by a Jorginho effort from distance. However, from a short corner, Napoli's new signing collected the ball on the left and swung an effort off the outside of the far post.
The home side were denied a penalty five minutes after the restart. Novaretti didn't get any of the ball as he bundled over Higuain, but the referee waved play on.
Cristian Ledesma's dangerous cross into the Napoli box was a yard behind the rest of his teammates. Keita Balde flashed a similar effort across the face of goal. However, Lazio's forays forward were few and far between and they soon found themselves back on the defensive. Ciani deflected Callejon's 25-yard effort wide, then threw his body in the way to block Hamsik's shot. Andre Dias slid in to intercept a Christian Maggio cross.
Brayan Perea saw a weak shot on the turn deflect out for Lazio's first corner of the game on 64 minutes. They couldn't capitalize and a poor delivery was easily cleared.
Berisha ran out to coax Higuain into taking a bad first touch, as the Argentine chased a through ball in the box. Dries Mertens replaced Insigne, who wasn't too happy at coming off and at some of the jeers coming from the home supporters. Jorginho pushed an effort wide from 25 yards and Lazio lost another defender to injury, when Andre Dias succumbed to cramp.
Reina remained untested in the Napoli goal as Ledesma blasted a free kick over the bar. Jorginho missed a glorious chance on 79 minutes, shooting over an open goal after Berisha failed to hold onto Mertens' teasing cross.
The breakthrough finally came eight minutes from the end, when Callejon's wayward effort was intercepted and turned in by Higuain. The forward backheeled the ball in mid flight from an onside position and the ball rolled past Berisha into the net.
Napoli: Reina; Maggio, Fernandez, Albiol, Reveillere; Jorginho, (Dzemaili 90) Inler; Insigne, (Mertens 69) Hamsik, (Pandev 76) Callejon; Higuain
Lazio: Berisha; Ciani, Novaretti, Dias; (Biava 72) Konko, (Cavanda 34) Onazi, (Gonzalez 46) Ledesma, Lulic; Anderson, Keita; Perea
Goals: Higuain 82 (N)