In front of more than 6,000 spectators Delestre ensured the cutrain was brought down on three days of high-level competition with a rendition of the Marseillaise.
With Qlassic Bois Margot, Delestre saw off competition from German Marcus Ehning/Plot Blue and Sweden's Rolf-Göran Bengtsson/Quintero La Silla in a closely fought jump off with 11 riders.
"With the victory in Mechelen at the end of December, it is one of the biggest performances of Qlassic who is only nine years old," Delestre said.
"In nine Grands Prix, he has scored nine clear rounds. He is truly an exceptional stallion. I felt something different the first time I rode him.
"I am also lucky because I can rely on Valentino Velvet, who is more experienced, then I can take my time to bring Qlassic to the top level."
Ehning, last year's winner with Sabrina, missed out on a double by just 28 hundreths of a second.
"My horse stumbled just after the number two so we wasted some time. I tried to make up for it, but it was not good enough," said Ehning, who finished second at the event in 2009 and 2010.