For trailblazer Billie Jean King, her leading role in the foundation of the Women's Tennis Association (WTA) half a century ago ranks above the many successes she enjoyed on court as a standout moment in her life.
King, 79, was the leader of nine players - the "Original Nine" - who formed the Virginia Slims Circuit in 1970 and three years later the WTA, which became the first truly global professional sports tour for women.
Following a meeting of around 60 fellow players at a packed conference room in London's Gloucester Hotel on June 21, 1973, King emerged as the president of the new organisation and began her push for equal prize money for women at the Grand Slams.
"It was pretty exciting. It was probably one of the most exciting days for me," King told Reuters during the French Open.
"Are you kidding? We finally had this. We had one voice. We had power and we were all together."
King won 12 Grand Slam singles titles and a further 27 in doubles but said the exhilaration of the early days of the WTA was unmatched by her considerable successes on court.
"Everyone thinks about what you win. That's third or fourth on the line," she said.
"I was getting no sleep, but I was so happy. It gave me so much buoyancy and adrenaline that every day I woke up I was like 'we have a WTA. God, now we can really make things happen'.
"That was just step one. You know me, I've got the vision up here. We still had so much to do, (but) I knew that it was going to happen."
'SIGN OF BELIEF'
The WTA has gone from strength-to-strength over the last 50 years with circuit restructures and bringing major worldwide sponsors on board helping drive growth.
This year, it announced a commercial partnership with private equity fund CVC Capital Partners worth a reported $150 million.
King said it was vital for the governing body to use that investment to grow the game.
"CVC coming on board was helpful," King said. "Anytime you can get money and investment and people who believe in you, it's very important. But there are also demands they have to get their investment back.
"Anytime you get a lot of money in something and you use it properly, that really helps push your support forward. It shows a sign of belief in us as well, which I think is really important psychologically."
All four Grand Slams now offer equal prize money for men and women, as do many of the other big tournaments, but King said her campaigning for pay equity was by no means finished.
"I've started to ask ... companies whether they spend as much on women's sports as they do on men's sports and start to put the heat on them, make them go 'oh, I hadn't thought about it' which is usually what you get," she said.
King said she hoped to one day see a unified governing body for men's and women's tennis amid increased cooperation between the ATP and the WTA in recent years.
"I want us all together," King said. "The guys think they're giving up something if they do something with us.
"But how are we ever going to be equal if we don't have more attention, more money, more everything?
"Sincere, great leadership comes from empathy and caring and not about yourself but about others and how we can help one another do better."