Frankel finished nearly two lengths ahead of Cirrus Des Aigles in the Champions Stakes at Ascot to cap his horse racing career with a 14th consecutive victory.
The unbeaten 4-year-old colt, who had $4.85 million in earnings with his $1.19 payday Saturday in England, will retire to stud.
"That is the end of it and he will retire," said owner Prince Khalid bin Abdullah. Frankel is expected to make more than $150 million as a sire, according to many analysts.
Frankel went off a 2-11 favorite at Ascot, where Queen Elizabeth II was among the 32,000 spectators.
He started slow before overtaking early leader Nathaniel and defending champion Cirrus Des Aigles with Tom Queally aboard.
“He's the best I've ever had, he's the best I've ever seen -- I'd be surprised if there's ever been any better,” trainer Henry Cecil said.