Napoli missed a chance to move provisionally level with second-placed Roma as it was held to 1-1 at Cagliari in Serie A on Saturday.
Earlier, Udinese picked up a valuable 2-1 win at fellow struggler Livorno in the final round of Italian league fixtures before the winter break.
Napoli remains third but could find itself 10 points behind leader Juventus if the two-time reigning champion beats Atalanta on Sunday. Roma plays Catania and would move five points ahead of Napoli with a win.
AC Milan plays city rival Inter in a highly anticipated derby.
"We had more chances than they did, but it wasn't enough," Napoli coach Rafa Benitez said. "A draw here is not a bad result, but it is for us because we're chasing the top of the table, even though it was very difficult here.
"Roma and Juve are doing great and that's the difference. They play each other (on Jan. 5) so we can close the gap. But we have to think about ourselves. We're doing better than last year, even after being in the Champions League as well, so what can we do? We need to be perfect."
Napoli was brimming with confidence after beating Inter Milan 4-2, but it was Cagliari which started the brighter and the Sardinian side took the lead in the ninth minute.
Davide Astori dispossessed Italy defender Christian Maggio and cut back for the unmarked Nene to fire home. The Brazilian thought he scored moments earlier but he was booked for firing at goal after the referee stopped play.
Gonzalo Higuain levelled 10 minutes later with a powerful penalty after Goran Pandev was fouled by Astori.
Jose Maria Callejon had a spectacular volley ruled out in the 73rd after the assistant referee spotted that the ball took the slightest of touches off Pandev, who was in an offside position.
"The pitch was really bad, the ball wasn't moving properly and towards the end we had to resort to long balls," Benitez added. "Then there's always the risk of a counterattack. But I think our defence was really strong. If we lacked anything it was in attack. Maggio said his mistake was because of the pitch, that the ball didn't bounce as he expected it to."
In Livorno, Udinese coach Francesco Guidolin handed a surprise start to Nico Lopez, who claimed the opener in the 11th minute.
The Uruguay Under-20 star won the ball off Emerson and raced into the left of the area before unleashing an angled drive into the far bottom corner.
Luca Siligardi levelled for Livorno shortly after the half hour as he feinted past Maurizio Domizzi and drilled across into the bottom left corner.
Thomas Heurtaux scored the winner in the 65th minute. Livorno goalkeeper Francesco Bardi did brilliantly to keep out Danilo's volley from an Antonio Di Natale corner but Heurtaux rushed in to tap in the rebound.
It was the defender's fourth goal of the season and makes him joint top goalscorer at the club with star striker Di Natale.
Udinese also hit the woodwork in first-half stoppage time when Bardi fingertipped Allan's deflected cross onto the crossbar.
Livorno, which has lost five of its past six matches, remained a point off safety ahead of the rest of the weekend games.