Napoli missed the chance to return to the top of Serie A in a stunning 2-1 loss to Como at the Stadio Giuseppe Sinigaglia on Sunday, as the title-chasing visitors' winless streak extended to four matches.
Napoli suffered their first defeat in 11 Serie A matches and remain second with 56 points from 26 games, one point behind reigning champions Inter Milan. Promoted Como are 13th on 28 points.
Napoli got off to a nightmare start when Kosovan centre back Amir Rrahmani gifted the lead to Como in the seventh minute by sending Matteo Politano's throw-in into his own net, with goalkeeper Alex Meret well off his line, to the despair of manager Antonio Conte.
Ten minutes later, forward Giacomo Raspadori pounced on some sloppy defending to slot the ball past Como keeper Jean Butez and level things up for Napoli.
However, winger Assane Diao netted a 77th-minute winner for Como with a stunning finish after picking up midfielder Nico Paz's precise pass. The 19-year-old Diao has now scored in three straight Serie A games.
Apart from the own-goal blunder, Napoli were the better side with 60 per cent possession in the opening half and looked more threatening.
But Como were far superior after the break and their efforts were not in vain as they clinched their second Serie A victory over Napoli, with the first coming in 1952.
Scott McTominay nearly put Napoli ahead in the second half, but Butez was in place to deny the midfielder. Rrahmani nearly snatched what would have been a crucial point for Napoli in the dying minutes of the game, but his shot went just wide.
Napoli next host Inter, who beat Genoa 1-0 at home on Saturday, in a blockbuster top-of-the-table clash at the Stadio Diego Armando Maradona next Saturday.