Australian jockey Zac Purton has guided Hong Kong's reigning champion Ambitious Dragon to victory in the International Mile at Sha Tin.

The Tony Millard-trained Ambitious Dragon was cleared by vets just hours before Sunday's race after he was found to be moderately lame in a hind leg a day earlier.

Purton brought Ambitious Dragon down the outside to overhaul Glorious Days who beat him last month in the lead-up race.

"I travelled like a winner the whole way, but I did last time so I wasn't going to start counting my chickens until I got to the line," Purton said.

The 29-year-old jockey has been based in Hong Kong for the past five years and enjoyed Group One success at Royal Ascot this year aboard Little Bridge in the King's Stand Stakes.