Billie Jean King and Emma Stone on tennis imitating life in 'Battle of the Sexes'

Emma Stone as Billie Jean King and Steve Carell as Bobby Riggs in the new film Battle of the SexesMelinda Sue Gordon/20th Century Fox

This story appears in ESPN The Magazine's Oct. 2 MLB Postseason Preview Issue. Subscribe today!

Fresh off watching Sloane Stephens top Madison Keys in the U.S. Open women's final at Flushing Meadows, Emma Stone is gushing about her personal color commentator for the match: tennis pioneer Billie Jean King, who sat next to her in the front row. "I don't think there was a moment when Billie Jean wasn't explaining something to me," the Oscar winner says.

To hear King tell it, though, Stone is a tennis natural, especially when it comes to bringing King's character to life in the upcoming Battle of the Sexes. Set against the backdrop of the women's movement in the 1970s, the film (in theaters Sept. 22) tells the story of the eponymous exhibition match between King and former world No. 1 Bobby Riggs (Steve Carell), who at the time asserted that "women belong in the bedroom and kitchen, in that order."

From the grounds of the U.S. Open, King and Stone spoke to ESPN about their awards-season contender, the ongoing fight for gender equality and, of course, the importance of good footwork.

ESPN: Billie Jean, what's your review of Emma's tennis game?
Oh, Jesus. [Laughs]
KING: She'd hardly played before this, but she 
did such a great job. She did really well on the footwork. One of the hardest things to do is to get the rhythm of a player, even just bouncing the ball before the serve. So I asked her, "How do you learn?" -- because everybody learns differently -- and she said when she learns a dance, she likes to be in front of a mirror. So I had her stand behind me, and we bounced the ball and tried to do the same rhythm.
STONE: If this had been a movie solely about tennis, I don't think I would've been able to do it. I had a great coach in [tennis choreographer] Vince Spadea and a great body double, and I trained a lot with my trainer. But for the most part I was really focused on the story and everything that was going on personally for BJ at that time and the struggle she was experiencing.

Billie Jean, what was it like watching yourself on the big screen?
I still haven't wrapped my head around it, to be honest with you. Emma was amazing. She worked so hard, and she did a remarkable job capturing my essence, my vulnerability, everything that was going on in my head at that time.
STONE: I felt an immense responsibility to Billie Jean. No one can quite live up to her, but I felt so lucky to sit down and talk to her. When I told her how much I wanted her to be happy with how the story was being told, she said, "You're never going to let me down. I know how hard you're working, and you're not going to let me down." I was so grateful.

How would you describe the impact of Billie Jean's win over Bobby Riggs?
Her impact was immeasurable. The match was entertaining, but it was also a huge vehicle for equality. And it changed the sport. Billie Jean said that the next weekend, you couldn't get on a court because everyone was playing tennis.

John McEnroe recently made headlines for saying Serena Williams would be the 700th-ranked male player. Why are we still debating this?
We never claimed we're better. It's only guys who talk about it. We know we'll never be better because you have androgens and we don't. Doesn't mean we can't be as entertaining. I don't think the 700th male can beat Serena, 
but that's not the point.

Still, it seems the battle has shifted away from the field and into boardrooms, from Silicon Valley to Hollywood, for equality and equal pay.

STONE: Well, I think in some ways [the movie] business is more circumstantial. The bigger picture that I like to focus on is the fact that equal pay has not been achieved across the board in America. It's imperative that in all industries, in all places of work, it's a fight that's continuing on.

What do you hope the film adds to the national conversation?
I hope the film helps the fight for equality. Sports teaches us leadership and resilience, because you have to lose a lot to win a lot, and I think it carries over into the boardroom, into family life, in helping children believe in themselves, in empowering women to stand up for themselves and to know it's OK to be ambitious.

While we're seeing more women in new roles in Hollywood and the sports world, what barriers remain that you'd like to see addressed next?
There was research about two years ago that men are hired on potential and women are hired by performance. We have to stop always thinking of women for their performance and start thinking about their potential. You have to believe in people and empower them to open up possibilities.