كتب : Omar AbdelAziz
A controversial first-half goal from Diego and a brace from veteran Alessandro Del Piero bought Ciro Ferrara some time in Turin, following four defeats in the last five matches.
Juve now lock horns with Serie A champions and current leaders Inter, who beat Livorno last month.
AC Milan have also booked their last-eight place with a narrow 2-1 win over third-tier Novara, courtesy of goals from Filippo Inzaghi and Mathieu Flamini.
Juventus 3-0 Napoli