New Zealand's Tim Price completed a husband and wife double with victory at the Land Rover Burghley Horse Trials.
Four months after wife Jonelle won Badminton Horse Trials, Price sealed Britain's other major four-star title.
A clear showjumping round on Ringwood Sky Boy helped Price hold off British world number one Oliver Townend.
His score of 27.3 penalties beat Townend and Ballaghmor Class - last year's winning Burghley combination - to the £95,000 first prize.
"Sky Boy deserves a good day - so often we nail two out of the three phases, so to finally pull them all together in a major competition is fantastic," said Price. "This win means everything and I'm super proud of my horse."
Townend ended on 31.9 penalties and took £50,000 for second spot. He also finished 12th aboard this year's Badminton runner-up Cooley SRS.
Townend has now had two firsts and two seconds in his last four four-star competitions, and he is set to remain world number one when updated rankings are published next week.
"I couldn't he happier with the performances of my horses this week," Townend said.
"I have been beaten by a very consistent, top-class pairing, and my horses have hopefully got an awful lot of years to go."
Multiple Burghley champion Andrew Nicholson was third on Swallow Springs, with Sarah Bullimore and Reve du Rouet fourth, Piggy French and Vanir Kamira in fifth and Harry Meade on Away Cruising sixth.