Napoli drew 1-1 with ten-man Genoa on Sunday to ensure that Juventus will have to wait another week to seal an eighth consecutive Serie A title.
The champions have a 20-point advantage on second-placed Napoli, who they have beaten in both their head-to-head clashes, with seven games to go.
Juventus, who beat AC Milan 2-1 on Saturday, needed Napoli to lose to win the Scudetto for the 35th time, ahead of their Champions League quarter-final first leg against Ajax next week.
A draw next weekend at lowly SPAL would be enough for Massimiliano Allegri's side to win the title which would be the first in Italy for Cristiano Ronaldo.
Despite their numerical advantage, Napoli struggled to contain the visitors who inflicted the only league defeat this season on Juventus last month.
Genoa went a man down when Stefano Sturaro was sent off on 28 minutes following a VAR review for a diving studs-up tackle on Allan.
Dries Mertens blasted in the opener on 34 minutes, but Darko Lazovic pulled Genoa level just before the break.
Genoa goalkeeper Ionut Radu ensured his 14th-placed side went away with a point with a string of fine saves including two late on Mertens and Kalidou Koulibaly.
"It was an unexpected performance that makes an alarm bell ring, if we play like this in London, then we're in trouble," said Napoli coach Carlo Ancelotti ahead of next week's Europa League game against Arsenal.
"We absolutely must wake up, demonstrate the value and potential that this group has and find our true identity.
"Luckily we have four days to fix things."
missed chances
Atalanta missed the chance to move fourth and into the Champions League berths at the expense of AC Milan with a 0-0 draw against Inter Milan at the San Siro.
The side from Bergamo were without suspended Colombian striker Duvan Zapata, who has scored 20 Serie A goals this season, and had to settle for a point as Inter consolidated third position.
Inter are five points ahead of city rivals Milan who are ahead of Atalanta on goal difference.
Mauro Icardi returned to the San Siro for the first time since a defeat by Bologna on February 3, and was greeted with a mixture of whistles and cheers from the home crowd.