By Terry Daley
ROME, Dec 21 (Reuters) - Napoli's bid to claim a first Serie A title for almost a quarter of a century received a severe jolt when they drew 1-1 at Cagliari on Saturday.
If Juventus win at lowly Atalanta on Sunday, third-placed Napoli will be 10 points adrift of the leaders going into the winter break.
Gonzalo Higuain equalised for Rafael Benitez's men with a 19th-minute penalty, his ninth league goal of the season, after Nene had put 11th-placed Cagliari in front early on.
Napoli, who last lifted the title in 1990, were unlucky in the 72nd minute when a stunning volley from Jose Callejon was disallowed for the narrowest of offside decisions.
Benitez's team have 36 points from 17 games, two behind unbeaten AS Roma who host Catania on Sunday and seven adrift of Juve.
"It was difficult to play because the pitch was really bad and trying to move the ball quickly and accurately wasn't easy," said Benitez.
"We had more chances than they did but that's not enough. We should have scored two or three goals."
Goals from Nicolas Lopez and Thomas Heurtaux saw 10th-placed Udinese win for the first time in four matches, 2-1 at third from bottom Livorno.
Francesco Guidolin's side moved a point clear of AC Milan who play city rivals Inter on Sunday.
Napoli may have to resume after the winter break without goalkeeper Pepe Reina who pulled up with a thigh injury after collecting a misplaced pass at the end of the first half.
Cagliari had put the visitors under intense pressure in the early stages.
The home team achieved a reward for their enterprising play when Davide Astori robbed a dozing Christian Maggio on the edge of the area and perfectly cut the ball back to Nene who produced a low left-foot finish.
Astori also played a role in Napoli's equaliser. He was penalised for a soft-looking challenge on Goran Pandev by referee Paolo Valeri and Higuain fired home his spot kick.
Benitez's side had far more of the play in the second period but struggled to break down a well-drilled Cagliari team.
Napoli thought they had snatched the three points when Callejon met a looping clearance with a beautifully-hit volley that flew past a crowd of players and into the bottom corner of the net, only for the linesman's flag to cut the celebrations short.
"We can't control what other teams are doing. Roma and Juve are doing really well," said Benitez.
"We're doing better than we did at the same point last year ... what else can we do?". (Editing by Tony Jimenez)