Before the advent of the
Open era of tennis competitions in April 1968, only
amateurs were allowed to compete in established tournaments, including the four
Grand Slams. There was no prize money and players were compensated for travel expenses only. However many top tennis players turned
professional to play legally for
prize money in the years before the open era. They played in separate professional events, mostly on tours involving head-to-head competition, but also in professional tournaments as the biggest events on the pro tour. Professional tournaments, in particular the professional Majors, usually only had a men's draw.