An outstanding end-to-end contest in Rome saw Rafael Benitez's men return to form and bring a run of three straight defeats to an end.
The thrilling away win, courtesy of a double from the Argentine and one goal each from Goran Pandev and Jose Callejon, snaps a run of three successive defeats and brings Rafael Benitez’s men back within six points of Juventus at the top of Serie A.
Lazio netted through a Valon Behrami own goal and a late Keita strike, but despite having the better of the first half, the hosts fell away after the break and have now gone five league matches without recording a win.
Napoli now sits 14 points ahead of the capital club and had to work hard to make the points safe in an exciting encounter which did not reflect positively on the defensive play of either side.
With Miroslav Klose ruled out with injury and Stefano Mauri suspended for the hosts, Brayan Perea was handed a start in attack. Pablo Armero was passed fit for Napoli, who were still missing Marek Hamsik.
Lazio enjoyed the better of the opening 20 minutes. Antonio Candreva flashed an effort wide after good work from Senad Lulic before Hernandes forced Reina into action with a powerful strike from the edge of the box.
Candreva was heavily involved in the early action and he again kept the Spanish goalkeeper busy before linking with Perea to set up ex-Sevilla man Abdoulay Konko, who failed to find the target despite having significant time available, prompting Reina to voice his frustrations at his defenders.
Napoli had only threatened through Jose Callejon almost taking Federico Marchetti by surprise but it was the impressive Higuain opened the scoring in the 24th minute.
Gokhan Inler won possession in a dangerous area and fed the former Real Madrid striker, who then had too much skill and pace for Michael Ciani and Konko before sliding to divert his shot past Marchetti to cap an excellent individual goal.
That effort had come slightly against the run of play and it was only seconds before Lazio was back on level terms. The hosts immediately attacked and Candreva’s cross took numerous deflections and Behrami could only turn it into his own goal in a dreadful defensive episode for Benitez’s men.
After a chaotic spell of the game, the visitors began to assert more authority over proceedings and they had the ball in the net for a second time, only to for Higuain to see his effort ruled out for offside after Marchetti had parried Lorenzo Insigne’s effort.
But it was Lazio which shaded the first half and they would have taken the lead five minutes before the break after a disastrous Napoli defensive mix-up only for Hernanes to waste a one-on-one opportunity before Candreva struck wide just before the interval.
The home side initially started the second half more brightly too, with Hernanes, keen to make up for his earlier miss, bursting past Behrami and shooting narrowly off-target.
But a decisive moment arrived six minutes into the half – one from which the hosts would never fully recover. Lorenzo Insigne’s free kick found Higuain, who lofted a cross toward the back post. A scramble ensued, with Pandev eventually showing strength to turn amongst the bodies and find the net.
With no immediate response to the goal this time around, Napoli began to take more control and Higuain flashed an effort across the face of goal from a difficult angle after being found by a lovely pass from Pandev.
Lazio was generally not as threatening after the break but did briefly press for an equalizer in the final with two chances on 65 minutes. A sliced pass from Inler inadvertently gave Lulic an opportunity, but his effort deflected poorly into the arms of Reina before Stefan Radu came close with an impressive long-range attempt.
The game was all but over in the 72nd minute, though, when Higuain struck again. Lorik Cana was unable to deal with Pandev’s through ball, and the striker raced onto the pass to slot a trademark finish past Marchetti and end the game as a contest.
Brief hope of a stunning comeback was raised with one minute to go when 18-year-old substitute Keita somehow bamboozled the Napoli defense with a solo run and smashed a shot high into the net past Reina.
But any hope of a dramatic equalizer was ended when one of the visitors’ substitutes, Dries Mertens, superbly won the ball from Ciani and fed Callejon, who made no mistake to seal the three points.