The more things change, the more they stay the same, the age-old adage goes. At a precarious time in the U.S.'s political and social history, it is far too easy to grow disheartened as those in power aim to strip away the hard-won rights of citizens who have for too long been treated as less than. Sometimes, though, it takes but a single soul to make a seismic shift, enlightening the public consciousness in ways which will hopefully carry down through generations. When reigning female tennis champ Billie Jean King accepted the challenge of competing against retired legend and self-proclaimed male chauvinist Bobby Riggs in a televised 1973 match, the promised $100,000 payday was beside the point. Sick and tired of the gross inequality, the gender stereotyping, and the unapologetic misogyny running rampant in her profession and throughout the country at large, Billie Jean had something to prove. No, women weren't too emotional. No, they weren't inferior—less fast, less strong, holding less stamina. No, their rightful place was not in the kitchen serving the men around them. Billie Jean was every bit as talented and able-bodied as any male tennis player, and she wanted the world to take notice.

Written and directed by Jonathan Dayton and Valerie Faris (2012's "Ruby Sparks"), "Battle of the Sexes" is a stirring, affectionately felt biopic about a necessary milestone in sports history. While the film is a veritable on- and off-court rally between Riggs and King, moving back and forth as both their lives track toward their fateful confrontation on the court, Billie Jean's story is significantly more involving and dynamic. At the top of her professional game, declared the most successful female player of all time, King uses her stature to fight for parity with her male counterparts. When she is rebuffed for calling attention to the fact that the men's winnings are 8 times what the women make, she cuts ties with the Lawn Tennis Association, assembles together her fellow professional lady athletes, and starts a rival league alongside tough-talking business partner Gladys Heldman (Sarah Silverman).

It is during this inaugural Virginia Slims Women's Tennis Association tour that the married King experiences a profound sexual awakening, falling for alluring hairdresser Marilyn Barnett (Andrea Riseborough). Aware of the ramifications which could occur if their tryst went public, King nonetheless is drawn to this new woman in her life, someone who makes her feel differently than anyone has before. When King's main rival, fellow champion player Margaret Court (Jessica McNamee), catches wind of Billie Jean and Marilyn's romantic relationship, it appears for a time that she is too conveniently being set up as a two-dimensional villain. The screenplay surprises, then, by not treating her as such, her intolerant knowledge kept largely between the two women. A forward-thinker and a natural activist, King initially turns down Bobby Riggs' offer to play him—in a televised primetime special on ABC, no less—because she doesn't want to bow to what she sees as a sexist stunt. Her path toward having second thoughts and finally accepting his invitation is a pleasure to watch unfold, the very reason she originally said no becoming the foremost reason she decides she must go through with the competition.

Emma Stone (2016's "La La Land") is sublime in her portrayal of Billie Jean King, weaving a complex tapestry of a woman whose baby steps toward personal liberation coincide with a much larger symbolic fight for equality. In lesser hands, she might have been written as an unblemished exemplar, but not here; she makes mistakes like anyone else, aware that her unfaithfulness to husband Larry (Austin Stowell) is only destined to hurt someone she loves but with whom she is not in love. Stone is believable swinging a racket but it is the light, the intelligence, and the fierce determination she gives this juicy part which most endures. A late scene set in the locker room post-match is especially powerful, the weight of her accomplishment and the deeper meaning behind it unleashed in a cathartic burst of emotion.

In comparison to the riveting Billie Jean thread of the narrative, the segments focused on Bobby Riggs are more basic and streamlined. Depicted as a grand-standing showman who wears his chauvinism like a badge of honor, Riggs is a 55-year-old gambling addict in a rocky marriage to Priscilla (Elisabeth Shue) who hopes to cement his virility and earn a fat paycheck by going up against the 29-year-old King. Because he is set in his ways, there isn't as much room for personal growth or a tracking arc. Steve Carell (2014's "Foxcatcher") lends Riggs enough charm for one to understand why the public liked him. Whether he believed every bigoted thing he said or not, he played right into his base (sound like someone else who might be running the country in 2017?), and Billie Jean knew this.

The entire ensemble cast is terrific. Andrea Riseborough (2016's "Nocturnal Animals") is charismatic and understanding as Marilyn, drawn to Billie Jean before she even realizes who she is. As the colorful, smoke-'em-if-you-got-'em Gladys Heldman, Sarah Silverman (2017's "The Book of Henry") blows in and out of scenes, owning each one of them. Elisabeth Shue (2012's "House at the End of the Street") is somewhat confined by her limited development as Bobby's wife Priscilla, but nonetheless gets a few moments to shine as she wrestles with her feelings for a husband who cannot be the man she longs to have. Bill Pullman (2016's "Independence Day: Resurgence") chews into his supporting turn as ex-tennis ace and commentator Jack Kramer, the most vocal of the sexist pigs with whom Billie Jean butts heads. Alan Cumming (2010's "Burlesque") is warm and likable, someone Billie Jean feels she can turn to, as the gals' out-and-proud fashion designer Ted Tinling. And, as Billie Jean's husband Larry, Austin Stowell (2015's "Bridge of Spies") brings a touching sense of devotion and rejection to his scenes as he grapples with a silently crumbling marriage.

"Battle of the Sexes" culminates in that famous 1973 tennis match between Billie Jean King and Bobby Riggs at the Houston Astrodome, and knowing who ultimately wins does nothing to take away the tension and anticipation of its outcome. It's a rousing finale for a sensitive, fair-handed docudrama with grander aims than the typical sports pic. Period details, from costumes and hairstyles down to soundtrack selections (George Harrison's "What Is Life," Tommy James and the Shondells' "Crimson and Clover," and Elton John's "Rocket Man" are all well-utilized), are top-notch, while the gender politics of its story are treated without compromise. Indeed, much of the anti-women viewpoints and verbiage would be difficult to believe if they weren't still occurring today. The not-so-secret weapon of "Battle of the Sexes" is Billie Jean King herself, and Emma Stone's impassioned turn playing her. In her showdown with Bobby Riggs, she reclaims her time, all right, and not a millisecond too soon.