Piotr Zielinski and Lorenzo Insigne scored in the second half as struggling Napoli shocked champions Juventus 2-1 to spoil coach Maurizio Sarri’s return to the Stadio San Paolo on Sunday.
Juve missed the chance to open up a six-point lead on Inter Milan at the top of the table, after Antonio Conte’s side were earlier held 1-1 by Cagliari, their third consecutive draw.
Zielinski broke the deadlock after 63 minutes finishing off a rebound after Insigne was denied by Juve goalkeeper Wojciech Szczesny.
Insigne volleyed in a second after 86 minutes to an explosion of joy among the crowd.
Cristiano Ronaldo pulled a goal back as the game headed into injury time for his 13th goal in nine consecutive games in all competitions.