David Simpson clinched victory in the puissance at the London International Horse Show at Olympia after clearing 2.20metres on Richi Rich.
The young Irishman dazzled a packed crowd on the event specialist and managed to pip Belgian rider Karline de Brabander atop Fantomas de Muze to the top prize.
"It gives you the tingles when you land," Simpson said.
"You don't get a better wall jumper than my horse and, for atmosphere and intensity, this win is right up there as one of my best moments in show jumping. I really wanted my first proper win to be here at Olympia."
Joseph Clayton finished in third riding Rockim, while his British compatriots William Whitaker and Guy Williams finished joint 10th and 12th respectively.
Earlier, 59-year-old John Whitaker triumphed in the Horsezone Santa Stakes on stallion Argento, while young Dutchman Maikel Van der Vleuten topped the standings in the Kingsland Christmas Pudding Stakes on VDL Groep Eureka.