Lorenzo Insigne put the brakes on Juventus' Serie A title challenge on Saturday as his 100th Napoli goal was enough for a 1-0 win over the champions that took some pressure off coach Gennaro Gattuso.
Italy attacker Insigne's 31st-minute penalty secured three points for Gattuso, whose job is widely reported to be under threat after a poor run of results.
The 29-year-old scored the winner after Giorgio Chiellini had been caught by VAR officials striking Amir Rrahmani with his hand while challenging for the ball.
"We're happy with the result but most of all the display, because we worked as a team and fought together... We're still a united team and we brought the win home," said Insigne, who had missed his previous three penalties against Juve.
"I know the coach and my teammates have faith in me and that is enough."
The win puts Napoli fourth, level on 40 points with Roma and Lazio and two behind Andrea Pirlo's third-placed Juve, who had been in good form in recent weeks but could end the day 10 points behind leaders AC Milan.
Seven-time European champions Milan, chasing a first league title in a decade, face Spezia in Saturday's late match with a chance to extend their lead over second-placed Inter Milan to five points.
Inter host a Lazio side on a run of six straight league wins on Sunday night.
Gattuso, already without key players such as Dries Mertens, then lost goalkeeper David Ospina who injured himself in the warm up.
Replacement Alex Meret was a key to Napoli's win, making three crucial saves behind a backline missing starting centre-backs Kalidou Koulibaly and Kostas Manolas
The Italy international was perfectly placed in the 49th minute when he managed to catch Cristiano Ronaldo's flicked volley from point-blank range.
In the 56th minute Meret brilliantly pushed away a stinging Federico Chiesa strike which flew at him through a crowd.
With four minutes left, Meret made sure of a fine win when he got down to stop Alvaro Morata's well-struck shot a short distance from goal.
Earlier, Torino were held to a goalless home draw by Genoa which leaves Juve's city rivals just two points above the relegation zone.
Torino have drawn half their 22 matches but have only won twice all season.