Magician produced a stunning finish to win the Breeders' Cup Turf.
Ryan Moore rode Aidan O'Brien's Irish 2,000 Guineas winner to victory at Santa Anita after John Gosden's The Fugue appeared to have the race won.
"I had him in a lovely rhythm, nice and relaxed," said Moore. "He must be one of the best horses I've ever ridden."
Moore had another winner on Dank in the Filly & Mare Turf while Gary Stevens, 50, brought Mucho Macho Man home first in the Classic.
The victory for Dank, trained in Newmarket by Sir Michael Stoute, brought Great Britain's winning total to four at the 2013 meeting after triumphs for London Bridge, Chriselliam and Outstrip on Friday.
Magician gave O'Brien his fourth victory in the race but at first it looked like The Fugue would take the honours when William Buick hit the front from last year's winner Little Mike.
But Moore had other ideas and timed his charge to perfection, winning by half a length.
The Coolmore colt had not run since Royal Ascot, where he disappointed following an injury where he was spooked by a bird that flew into an equine spa, and was moved up from a mile to a mile and a half.
O'Brien, who hopes Magician can return next year, said: "Ryan gave him a wonderful ride - a big 'well done' to everyone involved, and especially to the lads for letting me move him up to this trip.
"The week before Ascot he knocked a hind leg in the stable and the trainer had the great idea to put him in the spa. He'd almost gone through his full swim when a sparrow flew in the door and between his ears, which caused him to jump out and bruise both his front legs.
"I probably shouldn't have run him at Ascot [St James's Palace Stakes], it was one of those freak things, but when Camelot had a setback a couple of weeks ago we were able to reroute Magician to this race off his long break."
Buick, who was unlucky on The Fugue in the Filly & Mare last year, was visibly upset after the race when the horse was led back in by owner Lady Lloyd Webber.
Moore's victory on Dank in the Filly and Mare gave Sir Michael Stoute his sixth Breeders' Cup win and a second success in this race after Islington in 2003, also at Santa Anita.
Andre Fabre's Romantica came second, half a length behind to make it a European one-two in a race run in record time.
Stoute said: "We came here with very high hopes and coming second or third wouldn't have been very good - in fact I think she should be unbeaten and if I am allowed to keep her next year she will show how good she is."
Mucho Macho Man hung on to give Stevens, 50, his first win in the Classic - America's richest race.
Stevens only returned to racing this year after retirement in which he took up acting and punditry roles.
He held off Will Take Charge, with O'Brien's Declaration Of War a close third.