At age 12, Billie Jean King was hit with an "epiphany" about the sport she played.
While she was daydreaming about tennis, the realisation that everyone who played tennis wore white clothes, played with white balls and had white skin led to the question: Where's everybody else?
"That was the moment I decided that for the rest of my life, I'd fight for equality for all," said King.
Now 74, the American is still battling, and she hopes each generation continues to fight for freedom and equality.
The former world No. 1 was in town yesterday, which was also International Women's Day, to launch the last edition of the BNP Paribas WTA Finals Singapore presented by SC Global. The season finale takes place from Oct 21 to 28.
Speaking to The Straits Times about the changes she hopes to see on the women's tour, King envisions a "rookie school" for young tennis players to learn that being a professional athlete encompasses more than just playing tennis.
Explaining her vision of having current players to "truly step up and be leaders for now and the future", she said: "Some will step up, some won't care but, if we can just get one or maybe two, like Serena and Venus (Williams) or Martina (Navratilova) and Chris (Evert), all of them ended up being unbelievable leaders."
King, who in 1973 founded the Women's Tennis Association (WTA) to unite all of women's professional tennis, is an icon for gender equality and social justice.
Three months after she founded the WTA, King defeated Bobby Riggs in a "battle of the sexes" match which was viewed by an estimated 90 million people around the world. The match inspired the film Battle Of The Sexes, which was released last year.
Acknowledging that male athletes have been speaking up more, she said: "Sometimes it hurts them with endorsements and other things, but I like it when players speak up. I hope somebody (on the women's tour) steps up, but a lot of them are young, it takes courage and you're going to get a lot of flak.
"You've got to be able to take the criticism, the most important thing is not to take anything personally, and then you can survive."
Asked if she minds the fact that she is asked more frequently about her legacy as an advocate for equality than her on-court achievements, which include 12 Grand Slam singles titles, King said: "I like what I've done off the court much more than on the court. Off the court's much more important to me personally, so I like it when you do, because that keeps it going forward."