Napoli took advantage of Juventus' postponed match and routed Cagliari 5-0 to open up a four-point lead in Serie A on Monday.
Jose Callejon, Dries Mertens, Marek Hamsik, Lorenzo Insigne and Mario Rui scored as Napoli won its 10th straight in the league and remained unbeaten away from home.
Second-place Juventus had its match against Atalanta on Sunday postponed due to a snowstorm. A new date for the game still has not been announced.
Napoli is chasing its first Serie A title since Diego Maradona led the club to its only two championships in 1987 and 1990.
"We're playing every match as if it's a final," Insigne said. "It depends on us. We've got to win always from here until the end. Juventus isn't giving up, it's a great squad. But we showed against Cagliari that we're in form."
Still, it wasn't all straightforward for Napoli at Sardegna Arena.
Cagliari strikers Leonardo Pavoletti, who is on loan from Napoli, and Han Kwang-song, who is from North Korea, were dangerous in the opening half hour.
Napoli then took control with its fast-paced passing wizardry.
Callejon scored near the half-hour mark after Allan pulled the ball back from near the end line.
Mertens then had the slightest of touches to redirect a cross from Elseid Hysaj.
After the hour mark, Napoli captain Hamsik finished off a counterattack with a rising shot from the edge of the area for his 99th goal in Serie A.
Insigne then converted a penalty and Mario Rui connected with a curling free kick in the 90th.