Italy international Antonio Candreva struck twice including a late winner as Lazio stunned leaders Inter Milan 2-1 on Sunday to throw the Serie A title race wide open.

Inter welcomed Stefano Pioli's men to the San Siro expected to restore their four-point lead on title rivals Fiorentina and Napoli after their respective wins over Chievo and Atalanta.

But despite Mauro Icardi levelling Candreva's fifth-minute opener just after the hour, Roberto Mancini's league leaders were stunned three minutes from time when Candreva hit his second to end Lazio's seven-game winless streak and bolster Pioli's bid to avoid the chop.

Inter's third defeat in 17 games left the Nerazzurri top of the pile but they now have a lead of just one point on Fiorentina and Napoli, three on champions Juventus and four on Roma, who occupy fifth spot.

AC Milan sit in sixth at eight points off the pace after Sinisa Mihajlovic's men battled to a 4-2 win away to Frosinone.

A bad-tempered finish rubbed salt into Inter's wounds, with Brazilian Felipe Melo issued a straight red card in the final minute for a spectacular karate kick on compatriot Lucas Biglia.

Moments later, Lazio midfielder Sergej Milinkovic-Savic was also issued his marching orders, for a second bookable offence.

In what was the final Serie A game of 2015, Inter's largely unexpected defeat should already have fans champing at the bit for the resumption of hostilities in two weeks' time.

In Florence, Nikola Kalinic broke the deadlock in the 20th minute and strike partner Josip Ilicic doubled Fiorentina's lead with a fine dipping strike to secure their 11th win of the campaign.

Atalanta, who stunned Roma 2-0 in the Italian capital a fortnight ago, had pledged to make life hard for Napoli in Bergamo.

But seven minutes into the second half Napoli captain Marek Hamsik beat Davide Bassi from the penalty spot and although Atalanta pulled level two minutes later thanks to Alejandro Gomez's low strike, Gonzalo Higuain restored the visitors' lead with a flicked-on header that beat Davide Bassi at the keeper's near post.

Napoli's Brazilian midfielder Jorginho saw red for a studs-up challenge, but Higuain put the result beyond doubt when he powered down the right and held off his marker to beat Bassi with an angled strike that stretched his goals tally to 16 from 17 games.

Higuain paid tribute to Napoli coach Maurizio Sarri when he told Sky Sport: "Few teams have come here and played well, but we did -- you can see from the result.

"I'm happy for the goals, I'm working hard and if I'm feeling good then it's all down to the coach, to the club and to my teammates."

Juve's patchy 3-2 win at Carpi came thanks to a Mario Mandzukic brace and Paul Pogba's 50th minute goal, the champions claiming a seventh consecutive victory as their comeback from a disastrous start to the campaign continued.

"We played well, until the last, disastrous five minutes of the game," Allegri told Sky Sport.

"It was important to win today but we knew it wouldn't be easy to defeat Carpi after their Cup elimination of Fiorentina."

Edin Dzeko was sent off for dissent in the second half at the Stadio Olimpico, where Alessandro Florenzi's close-range volley gave embattled Roma a 42nd minute lead against Genoa.

But 18-year-old Nigerian Umar Sadiq, who replaced Mohamed Salah eight minutes from the end, eased any late nerves when he ghosted in at the back post to head past Mattia Perin to score his maiden Serie A goal and spark wild Roma celebrations.

The 2-0 win ended a four-game winless streak for Rudi Garcia's men.

Florenzi followed his goal by hugging under-fire Garcia, who said afterwards: "Of course we're emotional, but it shows how important it was for us to give it everything tonight to try and win this game.

"We went down to 10 men for the last 15-20 minutes, so the lads deserve all the credit for holding on and coming up with the second goal."