Outstanding Perth mare Delicacy has run her last race after breaking down in her Perth Cup win.

Delicacy was lame after setting a Perth Cup weight-carrying record for a mare on Saturday and scans revealed the four-year-old had torn both tendons in her front legs.

She lugged 59kg to lead home a Cup trifecta for owner Bob Peters and his wife Sandra at Ascot and added the Group Two race to her Group One triumphs in last year's South Australian Derby and Australasian Oaks.

Named last season's Australian three-year-old filly of the year, Delicacy bows out after earning $2.1 million from 12 wins and five placings in 19 starts.

She is set to become a valuable broodmare for Peters, one of Australian racing's best-known owners and breeders who always has a large string of racehorses in work.