Napoli extended their unbeaten run in Serie A to 10 matches with a 1-0 win over SPAL on Saturday to cut the gap with leaders Juventus to five points.
Carlo Ancelotti’s side have won eight and drawn two games since losing to Juventus at the end of September.
While Raul Albiol’s winner reduced the deficit to the defending champions, Juventus can restore their eight-point advantage by beating AS Roma in Turin later on Saturday.
Defender Albiol headed in the decisive goal in first-half injury time, but Napoli required two excellent late saves from goalkeeper Alex Meret against his former club to secure the three points.
SPAL are without a win in their last eight games and occupy 16th place on 16 points.
Napoli’s attention now turns to their trip to San Siro on Boxing Day to face third-placed Inter, who are nine points off second place with a game in hand.