Prix du Jockey Club
Semblat became an apprentice jockey at a young age and rode his first winner at the age of 13 in 1910. For a time he rode both on the flat and over jumps, before specialising in the former discipline. He attracted the attention of some of the leading figures French racing and became closely associated with the Chantilly trainers William Cunnington and Frank Carter. Among the horses he rode for Carter were Mon Talisman (Prix du Jockey Club and Prix de l'Arc de Triomphe in 1927), Pearl Cap (Arc de Triomphe 1931) and Clairvoyant (Prix du Jockey Club and Grand Prix de Paris).