Marek Hamsik cancelled out Sami Khedira's early opening goal as Napoli drew 1-1 with Serie A leaders Juventus on Gonzalo Higuain's first return to Stadio San Paolo.
Roma's 2-0 victory over Empoli on Saturday had cut the champions' advantage and a trip to third-placed Napoli was always likely to provide a stern test for Massimiliano Allegri's side.
But Juve took the lead after just six minutes, Khedira playing a one-two with Miralem Pjanic after a powerful run through midfield and beating goalkeeper Rafael from close range.
Hamsik levelled for Napoli by finishing off a Dries Mertens throughball and the Belgian almost put his side in front only to be denied by the post, with neither side able to find a winner.
The draw will be welcomed more by Juve, who move six points clear of Roma with eight league games remaining as they seek a sixth straight title, while Napoli are four points ahead of fourth-placed Lazio in the battle for Champions League qualification.
The two sides will meet again at Stadio San Paolo on Wednesday for the second leg of their Coppa Italia semi-final, with Juve holding a 3-1 lead from the first game in Turin.
Napoli were dealt a blow when Pepe Reina, who had started every league game this season, could not recover from a calf injury to take the gloves and replacement Rafael was beaten by the first shot of the match after six minutes.
Khedira collected a loose ball in midfield and burst through two weak Napoli challenges before swapping passes with Pjanic and slotting a low first-time shot through Rafael's grasp to score his fifth goal of the season.
Hamsik drilled a good chance off-target after Napoli pressure forced a loose Giorgio Chiellini pass and the midfielder lashed another clear opening wide of the post on the half-hour.
Napoli continued to press against a deep-lying Juve defence and Mertens should have done better after finding space in the box, the forward instead shooting straight at Gianluigi Buffon.
A rare Juve attack saw Mario Lemina lash an effort wide, before Lorenzo Insigne went close with a curling strike and Napoli had the ball in the net after 55 minutes but the goal was correctly disallowed for offside.
Jose Callejon tapped the rebound home after Buffon blocked a Mertens shot with his legs and the attacker was clearly beyond the last defender, but Napoli would not be denied on the hour mark.
A neat reverse pass from Mertens freed Hamsik as the pair swapped passes and the captain made no mistake with a blasted finish into the roof of the net, giving Buffon no chance.
Napoli were then gifted a golden opportunity to take the lead when a poor Kwadwo Asamoah backpass sent Mertens through on goal, but the attacker could only hit the post from a tight angle after beating Buffon to the ball.
Higuain endured a quiet game and was whistled mercilessly by the unforgiving home supporters as his goalless run extended to five games, but the point is more useful to Juve than Napoli.