Justify has won the Kentucky Derby to give trainer Bob Baffert his fifth win in the famous race and veteran jockey Mike Smith his second.

Smith urged Justify out of the gates into a forward position with the race run on a muddy surface at Churchill Downs after rain all day.

The colt went on to beat Good Magic and Audible to become the first Derby winner since 1882 to win without having raced as a two-year-old.

Credit: AAP