England's William Funnell rode Cortaflex Mondriaan to victory at Hickstead's British Jumping Derby.
The 40-year-old beat Robert Smith on Jerry Maguire in the Osborne Refrigerators Trial by five seconds.
He now aims to become only the second rider in Hickstead history to land the Trial/Derby double on Sunday when he rides Mondriaan in the DFS Derby.
Funnell's bid for the double has only previously been achieved by Ireland's Eddie Macken on Boomerang in 1979.
Funnell said his main goal is selection for Britain's World Games team at Aachen in late August.
"I have bigger outlook this year than the Derby," said Funnell, whose wife Pippa has withdrawn from the World Games Event team.