|Inter's Samuel Eto'o challenges for the ball as Inter extend their lead at the top [AFP]
Inter Milan needed a helping hand from the referee to secure a late win against Fiorentina at the San Siro to secure three points and extend their lead at the top of Italy's Serie A.
Diego Milito scored from a penalty five minutes from the end after being brought down by Gianluca Comotto.
AC Milan rose to second after substitute Klaas Jan Huntelaar netted his first two goals for the club deep into injury time to seal a 2-0 win at Catania.
The Dutch striker has floundered since a close season move from Real Madrid but he finally showed his worth by powering in Filippo Inzaghi's layoff and then producing a perfect chip.
But it was misery for third-placed Juventus as Cagliari's Nene opened the scoring with a long range effort in the 30th minute that gave Juventus goalkeeper Gianluigi Buffon no chance and Alessandro Matri added a second from a counter attack just a minute from time.
Inter started strongly as Muntari Sulley missed two excellent chances in the first 15 minutes and Diego Milito was denied by Fiorentina goalie Sebastien Frey a minute later.
Portugal winger Ricardo Quaresma, making a rare start for Inter, then hit a cross shot just past the far post on the half hour.
Champions Inter, chasing their fifth straight scudetto, thought they had gone ahead early in the second half when Walter Samuel's header was controversially ruled out for shirt tugging.
Samuel's centre-back partner Lucio had two good chances but hit a fierce free-kick straight at Frey before heading wide from six yards.
Alberto Gilardino hit the post in Fiorentina's only real chance and Inter forward Samuel Eto'o continued his shaky form by wasting a late one-on-one with visiting goalkeeper Sebastien Frey.
Inter took an undeserved victory with a dubious penalty award after Milito flopped comically to the ground in the box under minimal contact from Gianluca Comotto.
Milito picked himself up to slot home the spot-kick.
"This was a very important match and Inter played well,'' Inter coach Jose Mourinho said.
"For 80 minutes my team played better and had the better scoring chances. We scored a fair goal and the referee ruled it out, but in the end the goal came.''
"The players played with confidence and showed no fear after the loss to Barcelona in the Champions League this week.''
"We kept working till the 85th minute and then got our reward.''
Juve, who lost at Bordeaux in the Champions League in midweek, have struggled to find fluency for most of the season under rookie coach Ciro Ferrara but were slightly unfortunate in Sardinia.
Nene opened the scoring with a rocket from just outside the edge of the area after half an hour and after sustained Juve pressure, including a strong penalty appeal, Alessandro Matri broke at the other end to seal victory for Cagliari late on.
Lazio's disappointing season drags on after a 0-0 draw against Bologna in Rome with their former coach Delio Rossi losing in his first league game in charge of Palermo, beaten 1-0 at Chievo.
Promoted Parma moved up to joint fourth with Sampdoria, beaten 3-0 by sixth-placed Genoa in Saturday's derby, thanks to a 1-1 home draw with Napoli.
Cagliari are seventh with Bari, AS Roma and Fiorentina just a point further back after 14 games.
Bari, who came up last season and have rejected two recent takeover attempts, came from behind to win 2-1 at home to bottom club Siena while Roma continued to improve with their own 2-1 comeback victory at lowly Atalanta.