English jockey Steve Drowne remains in a Hong Kong hospital with a suspected broken collarbone and punctured lung following a fall at the International meeting.
Drowne fell Nunthorpe Stakes winner Jwala crashed to the ground during Sunday's Hong King Sprint.
The Robert Cowell-trained mare could not be saved.
It is another blow for Drowne who returned from a year on the sidelines in March after being diagnosed with an enlarged heart brought on by a virus.
Cowell used Twitter to express his sorrow at the mare's death.
"Thank you to everyone for their kind, sympathetic words. Jwala was a special racehorse - I am especially proud to have been part of her life."
The race was won by Japan's champion sprinter Lord Kanaloa who defended his title when he beat Irish horse Sole Power by five lengths.
It was the final racetrack appearance by Lord Kanaloa who will begin stud duties in February.