The Parisian club has now won the season-opening cup on 14 different times.
Paris Saint-Germain needed a dramatic leveler followed by a perfect penalty shootout to overcome their arch-rivals in the Gulf and capture a record-extending fourth consecutive Trophee des Champions victory.
The European champions appeared to be sailing towards a comfortable triumph in the match between the Ligue 1 champions and the French Cup holders after Ousmane Dembele opened the scoring early on.
However, the southern French side fired twice in the closing moments to seize a surprise lead. First, Mason Greenwood scored from the penalty spot, before the defender inadvertently directed the ball into his own net for an own-goal.
In a remarkable turn of fortune, Goncalo Ramos snatched a crucial leveler in the dying seconds to send the match into a deciding shootout. The Parisian shot-stopper Lucas Chevalier then stood as the key figure, stopping decisive attempts from O'Riley and Hamed Traore.
In the shootout, Ramos, the midfielder, the full-back, and the young talent all scored successfully for PSG to complete a 4-1 penalty victory.
Now 14-time champions PSG, who met last season's Ligue 1 second-placed team Olympique de Marseille after completing a league and cup double, have now won this trophy for the 12th time in the last thirteen seasons.
