TOKYO - Deep Impact, Japan's top horse, stormed to victory in the Arima Kinen on Sunday, his last race before retiring to stud.

The 4-year-old colt beat stablemate and Melbourne Cup runner-up Pop Rock by three lengths to secure his 12th win in 14 starts. Emperor’s Cup winner Daiwa Major was third.

Deep Impact, widely considered the best thoroughbred in Japanese racing history, won the Japan Cup last month to soften the blow of a doping scandal at the Arc de Triomphe.

French racing authorities stripped Deep Impact of his third place in October’s race after testing positive for a banned substance.

“It’s been a wonderful two years riding Deep Impact,” jockey Yukata Take told reporters after romping home in front of 10,000 fans in Chiba.

“There was a lot of pressure to win but Deep responded fantastically as always. I’m over the moon.”

Deep Impact tested positive for the banned substance ipratropium -- an inhaled medication that aids breathing -- at the Arc at Longchamp on Oct. 1.

Ipratropium is permitted in Japan but Deep Impact’s handlers were heavily criticized for the mistake that left a blemish on the horse’s legacy.

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Take and trainer Yasuo Ikee promised to return for next year’s Arc before Deep Impact’s owner Makoto Kaneko decided to retire the 2005 triple crown winner at the end of the year.

Deep Impact’s stud rights have already been sold to a syndicate for $4.2 million.

“It’s emotional,” sobbed Ikee, whose reputation took a battering after the Paris doping controversy.

“What can I say? I just want to say a big thank you to Deep Impact.”