Napoli ended Juventus's hopes of securing a record seventh Italian Super Cup after snatching a dramatic 6-5 shootout win in the final that stretched to 18 nerve-jangling penalties in Doha's Jassim Bin Hamad Stadium.
Carlos Tevez fired league champions Juventus ahead twice but Gonzalo Higuain scored two equalisers to send to game to penalties.
Tevez looked to have won the game in extra time when he handed Juventus a 2-1 lead with a low shot into the bottom corner of the net. But with three minutes to go, Higuain also found the back of the net for a second time to set up the electrifying finish.
In a thrilling penalty shootout that saw both keepers produce a string of stunning saves, Buffon made three saves but his acrobatic efforts were not enough as Juve missed four spot kicks.
The shootout started ominously for both teams with Tevez and Jorginho failing to score.
Both teams then scored each of their next five penalties, before missing the next two.
When Kalidou Koulibaly put Napoli 6-5 ahead, goalkeeper Rafael Cabral finally brought the shootout to an end by denying Simone Padoin, allowing Napoli fans to celebrate a memorable upset victory.
As Rafa Benitez's side rejoiced at winning their second Super Cup, their first triumph in the competition since 1990, Juventus were left to reflect on the missed chances that denied them a third straight title in the competition.
The last time the teams met in the Super Cup final was in 2012 when the Turin giants secured a comfortable win in Beijing.