Britain's Olympic champion Charlotte Dujardin retained her World Cup title in Las Vegas after performing a stunning freestyle routine on Valegro.
The 29-year-old scored 94.196%, just outside the world record she set at the 2014 London International Horse Show.
Victory means she is the first rider to hold Olympic, world, European and World Cup titles simultaneously.
"The atmosphere out there was amazing. It's fantastic. I'm living the dream," said Gloucestershire-based Dujardin.
Dutch rider Edward Gal was a distant second on 84.696%, with Jessica von Bredow-Werndl of Germany in third.
Dujardin and Valegro delighted the sell-out crowd of 10,900 with their freestyle - a series of dressage movements performed to specially chosen music.
The rider said: "We had the whole crowd behind us. The American crowd are so enthusiastic."
Dujardin will now prepare for August's European Championships and is already looking ahead to next year's Olympic Games in Rio.
She said: "I love it and Valegro loves it. I don't have to force him to do it and we're as strong as ever."
American rider Steffen Peters, who finished in a provisional third place, was eliminated after blood was found on his horse's side, meaning automatic disqualification.