Former PSG attacker Ben Arfa scored in the shoot-out as Rennes triumphed 6-5 on penalties following Saturday's 2-2 draw at the Stade de France in Paris.
PSG led 2-0 but Thomas Tuchel's men surrendered a two-goal lead – Rennes rallying to claim the Coupe de France for the first time since 1971.
It was a satisfying evening for Ben Arfa, who spent 15 months frozen out of the PSG team before he was sold to Rennes last year.
"The result gave me an exceptional emotion. It had been a difficult year and we worked hard to get here," Ben Arfa – who shared an awkward exchange with Al-Khelaifi post-game – told France 2.
"We're satisfied for Rennes, the Pinault family and the club in its whole. It's an immense pride. It's special. Especially regarding president Nasser. You should never underestimate your opponent in life. One day or another, he will come back stronger."
Ben Arfa did not let up in the mixed zone as he mocked PSG's capitulations in the Champions League after squandering a lead to Manchester United in the last 16 this season, having suffered a humiliating exit at the hands of Barcelona in 2017
"We pulled off a Remontada, but PSG are used to that," Ben Arfa told reporters.