MILAN, May 14 (Reuters) - AS Roma provided an unexpected twist to the Serie A title race on Sunday with a 3-1 over leaders Juventus, who had needed only a draw to wrap up their sixth successive title with two games to spare.
Daniele De Rossi, Stephan El Shaarawy and Radja Nainggolan scored for Roma to end Juve's 16-match unbeaten run in the league after Mario Lemina had put the visitors ahead.
Juve's lead over Roma was cut to four points with two matches to play, with Roma having the better head-to-head record.
Napoli, who earlier kept up their freescoring form as they beat Torino 5-0 away, are one point further behind in third and also still have a mathematical chance of winning the title.
Juventus, aiming for a league, cup and Champions League treble, are still firm favourites, needing three points from their matches at home to Crotone and away to Bologna.
They return to the Stadio Olimpico to face Lazio in the Coppa Italia final on Wednesday.
Elsewhere, hapless Inter Milan lost 2-1 at home to Sassuolo, their fourth defeat in a row, and most of their hardcore fans walked out in protest in the 25th minute, leaving a banner on the curva Nord saying they had "gone to lunch".
Juventus coach Massimiliano Allegri rested several players, including Paulo Dybala and defender Giorgio Chiellini, but his side still went ahead with a simple goal.
Stefano Sturaro lofted a ball into the area and Gonzalo Higuain laid it into the path of Lemina to stroke home in the 21st minute.
De Rossi levelled four minutes later from a rebound after Gianluigi Buffon had made a double save.
The game turned in the 56th minute when El Shaarawy's shot took a slight deflection and spun into the net. Then Nainggolan played a one-two with Mohamed Salah and scored with a typically emphatic finish. Jose Callejon gave Napoli a seventh-minute lead at Torino, sending an angled drive past Joe Hart and into the far corner.
Lorenzo Insigne added a second goal on the hour, then Mertens surprised Hart at the near post to score the third before Callejon slid in Faouzi Ghoulam's cross for his second of the match.
Piotr Zielinski put the finishing touch as Napoli took their tally for the season to 86 goals.
Inter, who sacked coach Stefano Pioli on Tuesday, did no better under caretaker Stefano Vecchi as Pietro Iemmello scored either side of halftime to put Sassuolo 2-0 ahead.
Eder pulled one back for Inter but it did little to inspire his team or quell the protests.
There were bizarre goals elsewhere.
Chievo were left fuming when goalkeeper Stefano Sorrentino lost his boot during a clash on the byline but play was waved on and Fabio Quagliarella scored into an empty net to put Sampdoria ahead.
Roberto Inglese volleyed home early in the second half to give the Flying Donkeys a 1-1 draw.
Genoa lost 1-0 at relegated Palermo when their goalkeeper Eugenio Lamanna caught a harmless Andrea Rispoli header under the crossbar but stepped backwards into his goal and took the ball over the line with him.
Genoa's defeat left them with 33 points, only two ahead of Crotone in the relegation zone with Empoli sandwiched in between.
Crotone continued their bid for a great escape by beating Udinese 1-0 with a goal by Marcus Rohden while Empoli lost 3-2 at Cagliari. Palermo and Pescara are already down. (Writing by Brian Homewood; Editing by Clare Fallon and Pritha Sarkar)