Gonzalo Higuain took his Serie A tally to 18 goals as Napoli cruised to a 5-1 win at Frosinone to go two points clear of Inter Milan on Sunday.

Napoli went into their first away trip of the year in third place at a point behind Inter and tied on points with Fiorentina.

But Fiorentina’s shock 3-1 defeat to Lazio on Saturday whet Napoli’s appetite, and it grew considerably earlier Sunday when Inter suffered a shock 1-0 defeat to Sassuolo at the San Siro.

Against a Frosinone side fighting for top flight survival, Napoli cruised to a 12th win of the campaign that pushed them two points clear of Inter, with Fiorentina now in third place at two points adrift.

Fiorentina and Inter’s setbacks will be welcomed by champions Juventus, who face Sampdoria away in Sunday’s late fixture looking for a ninth consecutive league win that would push them up to second.

Coach Maurizio Sarri, who celebrated seeing Napoli go clear at the halway stage on what is his 57th birthday, continued to keep mum over his side’s chances of fighting for a first title since 1990.

“We’re doing well but there’s nothing to say we’re the strongest in the league. We don’t have the same certainties as some other teams,” Sarri, referring to four-time consecutive champions Juventus, told Mediaset.

“They’ve won four titles in four years, so you could say they’ve got something extra we don’t.

“I’m the only one who’s been consistent in saying that, even when Juve were down near the bottom of the table, they would come fighting back with a series of wins and that’s what they’re doing.”

Napoli started in promising fashion at Frosinone’s sun-drenched Stadio Comunale, Raul Albiol giving the visitors a 20th minute lead when he coolly flicked a volley into the net at the back post following a corner.

Until then it had been a balanced affair, but the floodgates were soon to open.

Higuain doubled Napoli’s lead from the penalty spot on the half-hour after he was fouled by Roberto Crivello and claimed his second in two crazy, second-half minutes that saw captain Marek Hamsik on target.

Frosinone’s defence seemed happy to back off as Hamsik ran towards the edge of the area before unleashing a drive that beat Massimo Zappino down low in the 59th minute.

Barely 60 seconds later, Higuain muscled his way through two defenders and powered into the area to beat Zappino down low as the ‘keeper came rushing out to block.

The goals took the Argentinian’s tally to 18 from 19 games, an impressive return given the league’s ‘Capocannoniere’ (top scorer) award has been won the past two seasons with 22 goals.

Coach Maurizio Sarri replaced Higuain with Manolo Gabbiadini 20 minutes into the second half, and six minutes later the striker hit Napoli’s fifth.

Jose Callejon’s pressing causing Leonardo Blanchard to spill possession on the edge of the area and when he set up Gabbiadini the fledgling Italy forward had time to pick his spot before curling his shot into the top left hand corner.

Napoli looked to be heading for their second 5-0 win of the season having routed Lazio by the same scoreline in September, but with nine minutes remaining Paolo Sammarco swung at a short pass on the right side of the area to beat visiting ‘keeper Pepe Reina with an angled drive.

Earlier, Inter coach Roberto Mancini lamented his side’s wastefulness in a defeat decided by Domenico Berardi’s late spot-kick for Sassuolo.

“Maybe we lacked some lucidity when it came to putting our chances away, but the penalty that came at the end was a terrible mistake. That’s football though,” Mancini told Sky Sport.

Sassuolo coach Eusebio Di Francesco responded: “I don’t think it’s right to reduce the outcome of this game to one episode and I don’t want to talk too much about refereeing decisions.

“But I can say that it was a clear and indisputable penalty.”