American Bill Tilden was the first player to turn professional, in 1930. In 1932 he promoted his own tour, playing around the world against Czechoslovakia's Karel Kuzeluth. This worked as a springboard for Ellsworth Vines, Fred Perry, Don Budge, Bobby Rigs, Jack Kramer and Pancho Gonzales to start pursuing their own professional careers.
At that time, professional tennis players were not allowed to play in the events organized by the ILTF (International Lawn Tennis Federation), the organization that ruled tennis in those days, and these events included the four majors: Australian Open, Roland Garros, Wimbledon and US Open. The game lacked a more formal organization and the matches were purely played as head-to-head duels. After the World War II tournament-format competition started taking place.