Australia's Edwina Tops-Alexander and her diminutive horse Cevo Itot du Chateau blew away a field including the Olympic, world and European champions to win the World Cup showjumping event in Geneva.
The start list contained 14 of the top 20 riders in the world rankings, but Tops-Alexander and her 16-year-old chestnut gelding clinched the win with a superb run against the clock on Sunday.
Western Europe series league leader Sergio Alvaro Moya of Spain rode last and came closest to matching them, but his time of 41.64s was still well outside the blistering 40.40s set by the Australian combination over a tough course.
The win in the sixth leg of the series put Tops-Alexander into the running for the World Cup Jumping Final in Sweden in April, causing a rethink about her schedule.
"I wasn't planning on it, but I just might have to go for it now," she said.
"This was so special. Itot is in such great shape and I really wanted him to win here in Geneva.
"To win the World Cup qualifier, in such a tough class, he is just fantastic."
The win came two weeks after Top-Alexander and Itot won the lucrative Global Champions Tour title for a second consecutive year, triumphing in a countback in the finale in Abu Dhabi.
Tops-Alexander said Itot's love of competition was the key to his great form at age 16.
"It's really easy with him. You just need to keep him fit and well. He loves competition," she said.
"When he comes into the ring he feels the crowd and he is really happy to be at shows. At home he's quite lazy."
Asked how it is that he could out-run much bigger horses, she replied: "He just has this really elastic stride, so you can take him back or ask him to go forward so easily.
"He's so good and so clever, and he's always rooting for you. He's so very, very brave".