The seven-year-old, trained by Carlos Laffon-Parias, tore through the field down the home stretch to win Singapore's biggest race of the year by three lengths from Hong Kong's Zaidan, while favourite Zazou ate up ground in the closing stages to finish fifth.
The Irish-bred Chinchon had disappointed in the Cup last year and, despite solid form since then, looked like one to avoid as he snorted, swaggered and sweated under the watchful eyes of a packed parade ring at Kranji racetrack.
However, once jockey Oliver Doleuze got on board, Chinchon got down to business.
Biding his time as Zaidan and Flax struck for home, Doleuze unleashed his mount 600 metres from home and Chinchon answered, striding to the line.
The victory was a poignant one for Chinchon's connections as trainer Laffon-Parias had to return to France before the race due to the death of his father.
"It's very special for me tonight, to win this beautiful race," a breathless Doleuze said after the race. "Especially for Carlos, who lost his dad yesterday."
In the S$1-million KrisFlyer Sprint, the absence of local sprint hero Rocket Man due to a ligament strain subdued the Singapore crowd and the mood darkened further when hot favourite Krypton Factor finished outside the places as Ato took the honours.
The Patrick Shaw-trained four-year-old reeled in Mr Big in the last few strides to win the 1,200-m sprint race to the delight of jockey Barend Vorster and owner Dennis Evans.
"I think the accolades must go to Barend for a fantastic ride, and to Pat for preparing him so well," said Evans. "He's not been at his best in his last few runs but tonight he's shown how good he is."