PSG thumped Ligue 1 rivals Monaco 4-0 in China on Saturday thanks chiefly to a brace from Angel Di Maria, with Christopher Nkunku and Timothy Weah also scoring.
Buffon was untested in Shenzhen, with Leonardo Jardim's side unable to muster any shots on target against their more illustrious opponents.
After his first competitive appearance for the Ligue 1 champions, Buffon thanked Juve in a lengthy social media post.
"Even at the age of 40 you can still be happy to win a supercopa,” Buffon posted on Instagram.
"Thanks again to Juventus who, with their culture of work, allowed me to reach this age in optimal condition to keep performing.
"Thanks to PSG, who found the necessary arguments to push me even further. Thanks to my new team-mates who allowed me to win another trophy and welcomed me with enthusiasm, courtesy and respect.
"And thanks to [PSG colleague] Kevin Trapp who, despite what I offered a few days ago, wanted me to find the number one shirt in my place [in the dressing room].
"Thank you Kevin, from my heart, and thanks to all those who allowed me to feel these emotions again."