Milan (AFP) – Lorenzo Insigne and Jose Callejon struck inside the opening minutes as classy Napoli kept their title hopes alive with a 2-1 win at AC Milan on Saturday.

A week after seeing Fiorentina stun leaders Juventus 2-1 to carve open the Serie A title race, AC Milan hoped to upset predictions at a packed San Siro.

But a year after Insigne’s double inspired the southerners to a famous 4-0 away romp, it took a superb second-half performance from Milan’s teenaged goalkeeper Gianluigi Donnarumma to limit the damage.

Napoli remain third but have reduced the gap on Juventus, who host Lazio, to one point. Roma are in second, also one point adrift before hosting Cagliari in Sunday’s late game.

Paraguayan Gustavo Gomez, 23, was drafted in for suspended Alessandro Romagnoli at right-back but he struggled in the opening stages as Napoli hit two goals in the opening nine minutes.

Dries Mertens escaped down the right to collect Allan’s through ball before finding Insigne on the left flank.

The Italy midfielder took a touch before firing a superb drive that Donnarumma got his fingertips to before seeing it fly into the top corner.

Insigne’s sixth goal of the campaign should have prompted a quick reaction, but Milan seemed to do the opposite.

Mertens, on 12 league goals since stepping in to replace injured Polish striker Arkaduisz Milik, earned his second assist of the game all too easily minutes later.

After coolly sidestepping Gomez, the Belgian’s ball in behind the Milan defence found an overlapping Callejon, who raced in to beat the onrushing Donnarumma down low from a nearly impossible angle.

A quickfire third was thwarted when Donnarumma rushed out promptly to block at the feet of Callejon, Mertens somehow fluffing a great chance close in moments later after racing through unchallenged to meet Allan’s long ball.

When Milan won a corner on 35 minutes it prompted the biggest cheer thus far, but Gomez glanced a header wide from Giacomo Bonaventura’s well-worked move with Suso.

But the stadium erupted moments later, Kucka pouncing on a loose ball following a moment of confusion between Jorginho and Tonelli to poke the ball past the onrushing Pepe Reina eight minutes before the interval.

Milan resumed in far more positive fashion but on-loan Chelsea midfielder Mario Pasalic nodded a header off the crossbar from Ignazio Abate’s cross on the right.

Moments later, the 21-year-old Croat won possession in deep, only to see his through ball for unmarked Bacca deflected by Raul Albiol, Reina happy to see the ball go past his upright.

From the corner, Sosa’s daisycutter was smothered by Reina and at the other end Donnarumma had to race frantically back to see Insigne’s audaciously attempted lob from distance edge just over on the hour before then launching himself in mid-air to palm away Hamsik’s smart cross for the unmarked Belgian.

Half-chances from Bacca then Suso were easily dealt with by Reina as Napoli’s defence held firm while Milan pressed up high.

At the other end Donnarumma palmed the ball to safety after Mertens, sent through by Insigne’s defence-splitting pass, went on a one-on-one.

After a great performance between the sticks, Donnarumma could have levelled for the hosts in attack when he raced upfield for their final corner, only for his header to go straight at Reina.

Earlier, teenaged forward Federico Chiesa’s first Serie A goal for Fiorentina put the cherry on a 3-0 win at Chievo which boosted La Viola’s Europa League hopes.

Fiorentina are up to eighth at 12 points off the lead.