Burnham Square was in a great spot until Admire Daytona, on the cusp of retreating himself, sawed him off at the half-mile pole triggering a check & prolonged loss of ground. He went from 8th to 12th before re-rallying to finish 6th. Where does he finish with a clean trip?
Not sure if this counts but Secretariat was considered a biomechanically perfect horse, like to an extent that you couldn't design a better one. He was also well-tempered and easy to train. His Triple Crown speed records remain unbroken 50 years later.