Thomas Muster is an Austrian former world No. 1 tennis player. One of the world's leading clay court players in the 1990s, he won the 1995 French Open and at his peak was called "The King of Clay". In addition, he won eight Masters 1000 Series titles. Muster is one of the nine players to win Super 9/ATP Masters Series/ATP World Tour Masters 1000 titles on clay, hardcourt and carpet.

A clay court is one of the types of tennis court on which the sport of tennis is played. Clay courts are built on a foundation of crushed stone, brick, shale, and other aggregate, with a thin layer of fine clay particles on top. Clay courts are more common in Continental Europe and Latin America than in North America, Asia-Pacific or Britain. The only Grand Slam tournament that uses clay courts is the French Open.