American Pharoah ended his career in style by becoming the first horse to complete a Grand Slam with an emphatic victory at the Breeders' Cup Classic at Keeneland.

Ridden by Victor Espinoza, the Triple Crown winner finished six and a half lengths clear of Effinex following a masterful front-running display.

Much excitement had surrounded American Pharoah's bid to make history, in his final race before retiring, and the three-year-old certainly did not disappoint.

"The people came to see this, and they got it," said trainer Bob Baffert.

Legendary jump jockey AP McCoy tweeted: "Great performance from the highest rated and most famous racehorse in the world #AmericanPharoah."

Golden Horn was denied victory earlier in the day as the Aidan O'Brien-trained Found triumphed under Ryan Moore in the Breeders' Cup Turf.