Napoli are right back in Serie A title contention thanks to Kalidou Koulibaly's dramatic late header in their game with leaders Juventus.
They are now one point behind Juve, who have won the past six titles, with four games to go – and the Turin side have yet to visit Inter Milan and Roma.
Napoli dominated play but failed to create clear chances until centre-back Koulibaly powered home Jose Callejon's corner in the last minute.
Juve did not have a shot on target.
However, Miralem Pjanic hit the post in the first half with a deflected free-kick.
"The city fired us up over the last few days and when we see all those fans accompanying us to the airport, it makes us very happy," said Koulibaly.
"We want to thank them and the best way of doing that was to win the game.
"Juve are a very strong side, but we proved Napoli can fight it out with them. The team has always believed in the Scudetto and will do until it's mathematically certain.
"We believe in ourselves, in our style of football, in our players and our staff. We proved that tonight."
It was only a third home league defeat for Juventus in the past five years. They had been unbeaten domestically since November.
Napoli have only ever won two Serie A titles, both with Diego Maradona in their side, most recently in 1989-90.