An outstanding contest in Rome saw Rafael Benitez's side return to form and spectacularly end a run of three straight defeats
The thrilling away win, aided by further efforts from Goran Pandev and Jose Callejon, curtailed a sequence of three successive defeats and brings Rafael Benitez’s side within six points of Juventus at the top of Serie A.
Lazio scored through Valon Behrami's own goal and Keita but, despite having the better of the first half, they fell away after the break and have now gone five league matches without recording a win.
Napoli are now 14 points ahead of the capital club having worked 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 captain Stefano Mauri suspended, Brayan Perea was handed a start in Lazio's 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 Hernanes forced Pepe Reina into action with a powerful strike from the edge of the box.
Candreva was heavily involved in the early stages 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 to pick his spot, prompting Reina to voice his frustrations at his defenders.
Napoli had only threatened early on through Callejon who almost took Federico Marchetti by surprise before 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 had too much skill and pace for Michael Ciani and diverted his shot past Marchetti.
But Lazio were soon back on level terms. Candreva’s cross took numerous deflections and Behrami could only turn it into his own net for a dreadful own goal.
After a chaotic spell, 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.
It was Lazio who shaded the first half and they should have taken the lead five minutes before the break after a disastrous Napoli defensive mix-up only for Hernanes to waste a glorious one-on-one opportunity.
The home side initially started the second half brightly too, with Hernanes, keen to make up for his earlier miss, bursting past Behrami and shooting narrowly off-target.
But the decisive moment arrived six minutes into the half – one from which the hosts would never fully recover. Insigne’s free kick found Higuain, who lofted a cross towards the back post. A scramble ensued, with Pandev eventually showing strength to turn and find the net.
With no immediate response from Lazio this time, 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 were generally not as threatening after the break but did briefly press for an equaliser 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 somehow unable to deal with Pandev’s through-ball and the striker raced onto the pass and slotted a trademark finish past Marchetti.
Brief hope of a stunning comeback was raised with one minute to go when 18-year-old substitute Keita bamboozled the Napoli defence with a solo run and smashed a shot high into the net past Reina.
But any hope of a dramatic equaliser 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.