The Race to Save Mastery Mastery, the undefeated colt, was born on Kentucky Derby Day and had the bloodlines and athleticism for stardom. Then one bad step ended it all. By JOE DRAPEMAY 4, 2017 https://www.nytimes.com/2017/05/04/sports/horse-racing/mastery-bob-baffert-kentucky-derby.html?