Aoife Clark came from behind to pip Izzy Taylor and lead home an Oxfordshire one-two at the Equi-Trek Bramham International Horse Trials in west Yorkshire.
Taylor, from Aynho, near Banbury, led throughout the dressage and cross-country phases on Orlando.
But Clark, who is based at Middle Barton, jumped clear in the showjumping on Fenyas Elegance to finish on a score of 46.2 penalties, which piled the pressure on he rival.
Taylor was last to go, but a fence down early in her round meant that Irish-born rider Clark triumphed on the ten-year-old chestnut mare, who she won the Blenheim International on last September.
The four faults gave Taylor a final score of 46.9, and left her in second spot.