Iran Press/ Europe: Victor Osimhen saw a late penalty saved by Wojciech Szczesny, but Raspadori was the quickest to follow it up.
Federico Chiesa looked to have salvaged a draw for Juventus after scoring in the 81st minute, as his low strike found the bottom corner.
A deflected Khvicha Kvaratskhelia volley had earlier put Napoli in front.
Juventus, playing for the first time since Paul Pogba's four-year ban for a doping offense was confirmed, missed chances of their own as Dusan Vlahovic hit a post with a chipped effort.
Defeat means second-placed Juventus are 12 points adrift of leaders Inter Milan, who have a game in hand against Genoa on Monday.
216
Read more:
Juventus 1 - Inter Milan 1
