Anmaat sprang a 40-1 shock in the Champion Stakes at Ascot as the outsider defeated favourite Calandagan.
French challenger Calandagan had been short of room during the race but made his way to the front before Jim Crowley came with a perfectly timed run on the winner, trained by Owen Burrows.
Royal Rhyme (25-1) was third in the big race on British Champions Day, while second favourite Economics was back in sixth.
Kyprios and Charyn were among the other winners on the country’s richest raceday, where £4m in prize money was on offer.
The Aidan O’Brien pair of Continuous and Los Angeles claimed the front spots as the Champion Stakes developed, with Calandagan among those pegged in behind.
Crowley also had to wait for a gap, but when it appeared, his mount surged through and won by half a length.
“He wasn’t going to run after he disappointed in France but this was his day,” said Crowley of the winner, who had finished fifth at ParisLongchamp this month.
Irish Champion Stakes winner Economics, losing for the first time this season, was found to have bled from his nose, said trainer William Haggas.