Ireland's Richie Moloney had just under a second to spare when winning Friday's speed class at the four-star show in Wellington, Florida.
The Kilkenny-born rider, accompanied by Alsvid, entered the competition several rounds after class leader Kent Farrington of the USA had posted the quickest time of the evening.
Moloney and his Equinimity LLC gelding took over a second off Farrington's time to post a mark that was out of reach for their opponents.
The USA's Ali Wolff came close, but Moloney had done enough to secure victory, with Farrington finishing third.
Conor Swail just missed out on a podium place after the Co Down man finished fourth on board Cita.
Moloney felt the competition suited Alsvid, saying "He's very good in these types of classes and has proven to be very consistent this season placing in the top three at least five times since the beginning of the summer. It was a strong class today, and I felt very good about his performance."
Meanwhile, Tipperary's Denis Lynch finished fourth in the Prize of Mitsubishi Speed class at the World Cup show in Madrid, Spain.