Tennis star Rosemary Casals, who fought for equal pay for women, reflects on progress made

Rosemary Casals has many titles, but she still isn't quite sure how to react when people call her a living legend.

The tennis star and equal pay advocate was one of just nine women who fought to close the gender pay gap between male and female tennis players early in her career. Casals began playing tennis in her hometown of San Francisco. Raised by immigrants from El Salvador, Casals learned the game at Golden Gate Park.

One day, she faced a fellow public parks player and soon-to-be icon: Billie Jean King.

"It left a big impression on me. I thought 'God, that's the way a pro's supposed to look,'" Casals, now 75, recalled. "We went and played the match. It was very, very close. And I remember after, Billie Jean saying 'You know, you're pretty good. You better keep with it, and I'll check up on you.' ... I definitely thought 'Well, if she can tell me that I'm pretty good, I better do something about it.'"

King, the world's number one player, soon became more than a rival. She and Casals became doubles partners and went on to win eight major championships in nine years together as tennis became a professional sport. Johnette Howard, an author and sportswriter, said both women had an "underdog mentality" and refused to "accept the status quo."