When the winner of the women's singles at the U.S. Open picks up her check for $2.6 million -- buck for buck the same as the men's champion -- she might well reflect that, if not for Billie Jean King's pioneering efforts, those riches might not exist.
Supreme champion on the court, battler for equality off it, King took on the male-dominated tennis establishment and won.
She was the driving force behind the formation of the Women's Tennis Association (WTA) in 1973, the same year she famously beat former men's grand slam champion Bobby Riggs in the "Battle of the Sexes" match in Houston.
"Everybody should thank her and shake her hand," King's fellow tennis icon Chris Evert told CNN's Open Court. "She put money in our pockets and provided a living for hundreds and hundreds of female athletes.
"Tennis is the frontrunner in all sports in equality, so she deserves all of the credit."
Forty years on, King, who turns 70 in November, has been celebrating the WTA's anniversary in a series of events which defined the role of women not just in sport, but in society itself.
The fledgling Virginia Slims tennis circuit for women professionals had been established at the start of the 1970s, but the leading players like King and Australian Margaret Court -- the all-time leading grand slam singles winner -- were still paid a fraction of the prize money available to their male counterparts.
The men had formed their own union -- the Association of Tennis Professionals (ATP) in 1972 -- and King was convinced it needed to be replicated for women.
Using her famous powers of persuasion, and with help from other key figures such as Dutchwoman Betty Stove, compatriots Rosie Casals and Nancy Ritchey and Britain's Ann Jones, a meeting was convened at the Gloucester Hotel in London, just before the Wimbledon championships.
Within a few short hours, the articles of the association were signed and the WTA was born.
"We finally all came together as one voice and having the power of one -- you know just one group. It made such a difference," King told CNN.
Martina Navratilova was then just starting out on her incredible career, and it was only later that she appreciated the significance of what had happened.
"My first year playing -- 1973, my first Wimbledon -- I had no idea what the association was, but being American and being a bit older, Billie Jean again had the foresight to get us organized just in time," the Czechoslovakia-born Navratilova told CNN.
Already an influential figure in the United States and helped by her then husband Larry, an astute lawyer, King had threatened to boycott the 1973 U.S. Open if equal prize money was not awarded.
As defending champion, King had considerable leverage and the organizers gave in to her demands. When Court won the 1973 title she received the same prize purse -- $25,000 -- as the men's champion.
But this concession was the exception rather than the rule in major sports.
Such male chauvinism was personified by former Wimbledon champion Riggs, a shameless self publicist, who made a fortune from gambling on his own tennis matches.
Seeing an opportunity to make more money, Riggs challenged both Court and King, claiming that even in middle age -- he was 55 -- he could beat the top women players.
King ignored him at first, but Court took up the challenge and played him in a match in California on May 13, 1973.
King had realized the significance of the occasion and had done her best to encourage the Australian to take it seriously.
"I said, 'Margaret it's not a tennis match, it's about social change, it's about social justice, it's about all the things we're working for,' and she goes, 'I don't'. She wasn't politically orientated!