Serena Williams hinted at retirement earlier this summer, but it’s not slowing her down at the US Open tennis championships, where she unexpectedly beat the number two seed player Wednesday. In an williams-us-open.html">essay for The New York Times this week, Billie Jean King wrote, “Her presence and politics raised the game. The technique, power and rhythm of her serve are unbelievable. It sets the tone for the intensity of her game. I don’t care what happens after that; I’m just there to watch her serve.”

King, who’s won won 39 Grand Slam titles and founded the Women’s Sports Foundation and the Women’s Tennis Association, spoke about Serena from the court after she won her first US Open match. She’s an iconic advocate for gender equality and social justice and was inducted into the International Tennis Hall of Fame in 1987. This year, she received the French Legion of Honor.

For this weekend’s bonus interview, from the Radio Times archive, we revisit our 2014 interview with Billie Jean King, in which she discussed her life, career and the state of tennis today.