Inter Milan fell further behind in the Serie A title race on Sunday after a scrappy 1-1 home draw with Champions League-chasing Roma left them 11 points behind leaders Napoli.

Matias Vecino equalised with a late header for Inter after Stephan El Shaarawy had capitalised on awful defending to clip home goalkeeper Alisson's huge clearance in the 32nd minute to open the scoring.

Uruguayan Vecino met a whipped Marcelo Brozovic cross to beat an outstanding Alisson, who had made two superb second-half saves from Mauro Icardi, and keep Luciano Spalletti's side in the top four, level on 43 points with third-placed Lazio and three ahead of Roma.

However they are winless in six games in the league and no longer look like title contenders, while Roma, who stay fifth on 40 points, have fallen even further behind after picking up just ten points from a possible 24 since beating Lazio in mid-November.

Eusebio Di Francesco's side are now 12 points behind Napoli, who extended their lead at the top to four points when Dries Mertens ended a long goal drought to give his team a 1-0 victory at Atalanta.

Belgian international Mertens's 65th-minute strike ended a league dry spell that stretched back to October 29, getting behind the defence and flashing his 11th goal of the season past Atalanta goalkeeper Etrit Berisha.

"He (Mertens) had shown some signs of improvement even without scoring goals, so the drought was relative. It was obvious he'd get back to scoring goals eventually," said Napoli coach Maurizio Sarri.

Atalanta are down to eighth after the loss and AC Milan's 2-1 win at Cagliari, which came thanks to Franck Kessie scoring twice to drag his team back from a goal down in Sardinia.

Lazio took third thanks to a thumping 5-1 win over Chievo in Rome that saw rising star Sergej Milinkovic-Savic bag a fine brace either side of half-time to put Lazio two up, after Chievo's Manuel Pucciarelli had equalised Luis Alberto's 23rd-minute long-range opener for the hosts.

Substitute Nani laid on Bastos to fire home a deflected fourth with seven minutes left, before the former Manchester United winger added a fifth three minutes later with a fine hit from the edge of the area.

"The boys are enjoying themselves, when we manage to go ahead we often score a lot of goals and that is a great hallmark," said Inzaghi, whose exciting team are now Serie A's top scorers with 53 goals despite having the league's leading scorer Ciro Immobile limp off with a muscle injury after 35 minutes.

- Quagliarella's Indian summer -

Sampdoria are three points ahead of Atalanta in sixth after Fabio Quagliarella fired an excellent hat-trick to down Fiorentina 3-1 in Genoa.

The 34-year-old Italian is enjoying something of an Indian summer and scored in the 30th, 60th and 68th minutes to continue Sampdoria's fine home record that has seen them gather 24 of their 33 points at the Stadio Luigi Ferraris.

"I am in an environment that I like a lot, a team in which I have a lot of fun and everything else comes from that," said Quagliarella, who has scored 15 times in 20 league appearances.

Bottom club Benevento's mini-revival came to a crashing halt with a 3-0 beating at Bologna, thanks to goals from Mattia Destro, Sebastien De Maio and Blerim Dzemaili.

Benevento had won two games in a row -- there first ever Serie A successes -- going into the winter break but remain on seven points and are now 11 points from safety after Crotone's 3-0 win at second-bottom Verona, which lifted them out of the bottom three.

Elsewhere, Simone Berardi saved a point for Sassuolo with a 1-1 draw at home to Torino after Obi had given the away side a 26th-minute lead, and Udinese played out another 1-1 draw with SPAL, who drop back into the relegation zone despite Sergio Floccari saving a point after Samir's 11th-minute opener.