A win for Genoa would have handed the Turin side the title with a record seven matches to spare.
They came closer than expected in spite of having Stefano Sturaro sent off after 28 minutes.
Their next fixture is away to SPAL on Saturday.
Genoa — the only team to have beaten Juventus in the league this season — were dangerous from the start as Goran Pandev fired a low shot just wide.
He then had a dipping effort tipped away by Orestis Karnezis.
Sturaro was sent off for recklessly lunging at Allan — the referee changing a yellow card to red after a VAR review.
But even after this, Genoa kept pressing as if nothing had changed and Karnezis had to tip a Christian Kouame shot over the bar.
Dries Mertens fired Napoli in front with a low shot from the edge of the area in the 34th minute, but not even that deterred Genoa.
After defender Koray Gunter had hit the post from a corner kick, Darko Lazovic met Pandev’s chip into the penalty area first time and drilled a low shot past Karnezis.
Napoli penned Genoa into their own half for most of the second half but Kouame remained a constant threat.
He nearly won it for the visitors when he forced a point-blank save from Karnezis on a rare counter-attack.
Genoa goalkeeper Ionut Radu then made two outstanding saves to make sure of a deserved point for his side.Share this News