Vincenzo Montella's side picked up their first win over the Bianconeri since 2012 thanks to a second half strike with the visitors also losing striker Paulo Dybala to injury
Manuel Locatelli's stunning strike earned AC Milan a 1-0 victory over Serie A leaders Juventus, who controversially had a Miralem Pjanic goal ruled out at San Siro.
Teenage midfielder Locatelli fired a sensational effort beyond Juve goalkeeper Gianluigi Buffon in the 65th minute, with Vincenzo Montella's side consequently moving to within two points of their table-topping opponents on his 200th Serie A match as a head coach.
The champions may feel hard done by, though, with Pjanic seeing a goal chalked off in the first half due to a debatable offside decision against Medhi Benatia.