Kildare jockey David Egan was on board as Mishriff powered home to land victory in the world's most valuable race, the 20million Saudi Cup in Riyadh.
The John Gosden-trained colt, owned by Prince Faisal, made his stamina tell over the nine furlongs after the two US heavyweights, Charlatan and Knicks Go, had gone head to head in the early stages.
Egan was able to stay on their heels as the big pair turned for home.
Knicks Go dropped away, leaving Mishriff to gradually reduce Charlatan's lead and get up in the closing stages. Great Scot finished third.
Speaking after the race, a delighted Egan said: "I can't believe it. He's an absolute champion. It's unbelievable."
From his Newmarket base, Gosden said: "It was a wonderful performance. He showed a lot of grit and courage, and he was able to go the pace of the American horses. It was great."
Now proven on dirt as well as turf, having won the French Derby last year, Mishriff would appear to have all the world's biggest races open to him.
But Gosden was keen not to be drawn on future plans, adding: "One race at a time."
Earlier in Riyadh, Willie Mullins' True Self broke American hearts as Hollie Doyle rode a tremendous late run to take the Neom Turf Cup.
The record-breaking British female jockey produced True Self to collar long-time leader Channel Maker close home and lift the £437,956 first prize.
Bill Mott's Channel Maker, a close third in the Breeders' Cup Turf, looked like he had the race in the bag when he slipped the field at the top of straight after soaring past long-time leader For The Top.
However, jockey Joel Rosario had not accounted for True Self's abundant stamina - and the eight-year-old started to reduce the gap.
With Doyle in full drive, True Self pulled away from Channel Maker to score by a length and a quarter. The pair were four and three-quarter lengths clear of Emirates Knight in third.
The well-fancied Tilsit, trained by Charlie Hills, had a good early position but was beaten a long way from home.
Space Blues made a winning return to action after a six-month break with a narrow victory in the stc Turf Sprint.
Winner of all four of his four starts in the summer, culminating in a first Group One success in the Prix Maurice de Gheest, the Charlie Appleby-trained five-year-old looks set for another lucrative campaign.
Krispen made the early running and was pressed by the former Richard Hannon-trained Urban Icon, who set sail for home in the straight.
Space Blues shrugged off his stablemate Glorious Journey, but had to knuckle down for William Buick to catch Urban Icon and last year's winner, Dark Power.
He managed it in the shadow of the post to score a shade cosily in the end from Dark Power, ridden by Frankie Dettori, with Urban Icon just behind in third.
