Joseph O'Brien became the youngest rider to ever win a Breeders' Cup race as he steered his father Aidan's St Nicholas Abbey to a famous success in the Turf at Churchill Downs.
Settled in mid-division by the 18-year-old, the Montjeu colt picked up superbly when angled out for a run.
Sea Moon and Ryan Moore had given chase to Brilliant Speed off the turn, but St Nicholas Abbey swamped them both, stretching clear in tremendous style. Sea Moon had no answer in second, with Brilliant Speed third.
A clearly moved Aidan O'Brien said: "It's very special, unbelievable. It was a wonderful ride, it's incredible. What can I say, he's an incredible rider. It's been one of the proudest days of my life, just unbelievable."
Joseph's mother, Anne-Marie, said: "I'm so excited, he gave it a super ride. It's fantastic. My heart was going 100mph, I could hardly stand up I was so nervous. We are so pleased to be here."
The winning rider said: "It's a dream come true. I was very happy with my position, I was very happy with the horse and he picked up when it mattered. They went a nice pace, I had to be patient and wait for the gaps, but when he got out he picked up well.
"I've been coming to the Breeders' Cup since I was very small, but to ride here and ride a winner - it's out of this world."
Coolmore partner Derrick Smith said: "This is way up there. We've always had faith in the horse and to see Joseph, it's a day from the gods. They have put so much work into everything. It's unbelievable for us.
"The horse showed all his brilliance today, we always knew it was there."
Teddy Grimthorpe, racing manager to Sea Moon's owner Khalid Abdullah, said of the Sir Michael Stoute-trained colt: "Sea Moon ran a blinder, however he wasn't helped by his sluggish start. We can't complain as he got in a super position to challenge and did everything he could. He is lightly raced and still a bit babyish."