For the first time, American Masters profiles a sports figure: Billie Jean King, a determined woman who has been a major force in changing and democratizing the cultural landscape. American Masters Billie Jean King premieres nationally Tuesday, September 10, 2013 at 8 p.m. on PBS (check local listings) to commemorate the 40th anniversaries of the Billie Jean King v. Bobby Riggs “The Battle of the Sexes” match on Sept. 20, 1973, and the founding of the Women’s Tennis Association (WTA) by King on June 20 of that year. This new documentary traces the incredible life of the single most important female athlete of the 20th century as her 70th birthday nears.