Reigning champions Juventus are certain to top Serie A at Christmas after a 3-1 win at Cagliari on Thursday in their final league game of 2014.
Early strikes by Carlos Tevez and Arturo Vidal and a Fernando Llorente counter in the second half put Juve out of sight before Luca Rossettini got a goal back for the hosts.
While Cagliari remain in the relegation zone after seeing their run without a win extended to eight games, Juve are now four points clear of nearest challengers Roma, who host AC Milan in their final game of 2014 on Saturday night.
This game and Napoli`s later clash with Parma were brought forward as champions Juventus and Rafael Benitez`s Cup holders will meet in Qatar on Monday in the Italian Super Cup.
Massimiliano Allegri`s Juve will head into that game buoyed by a routine win in Sardinia following successive league draws against Fiorentina and Sampdoria.
Cagliari were the only team in Serie A still without a home win to their name and Zdenek Zeman`s side saw that run continue as they failed to recover from a terrible start.
The game was only in its third minute when the visitors opened the scoring at the Sant`Elia stadium, Tevez following up to score his 10th goal of the campaign after Cagliari `keeper Alessio Cragno had saved from Giorgio Chiellini.
Gianluigi Buffon then saved well from Albin Ekdal at the other end but the Turin giants doubled their lead on 15 minutes thanks to a sumptuous Vidal strike.
When a low Patrice Evra cross from the left was only partially cleared by the home defence, the Chilean midfielder met the loose ball with a superb first-time curling shot into the right corner of the net.
Danilo Avelar fired into the side-netting late in the first half, but Cagliari had given themselves too much to do and Juve scored again five minutes after the restart when Llorente turned and shot inside the box, his attempt squirming under the body of Cragno and in for his fourth goal of the campaign.
Cagliari got one back on 65 minutes when Rossettini stole half a yard on Vidal to head in a free-kick from the right wing at the far post, but that did not stop it being a good night for Allegri on his return to his old ground.
Allegri played for Cagliari in the 1990s and did well in two years there as coach before taking over at AC Milan in 2010.