LOS ANGELES — Ronda Rousey spent a year as a bartender after she turned 21, partying every night and wondering what to do with her Olympic bronze medal in judo.

When she first saw mixed martial arts on television, her friends warned her away. This complicated new cage-fighting sport was too violent, too primitive, too unregulated.

“That just made me really want to try it,” Rousey said.

Six years later, Rousey is nothing less than the face of the UFC, the young sport’s dominant promotional company. She has never lost a fight, reigning as the bantamweight champion for two year’s.

Rousey has become an actor, a model, a celebrity endorser and one of the world’s most prominent female athletes during her meteoric rise, but she realizes she hasn’t done it alone. Women’s MMA is surging in prominence with Rousey at the forefront, and the sport gets its biggest showcase yet this weekend when two women’s fights will headline a UFC card.

“The women are a force in this sport,” Rousey said. “They don’t need anybody’s help to sell the sport. They sell themselves to the fans, and the thing about women’s MMA is that it brings new fans into the sport as well. They don’t just bring the traditional fans. When the women are featured in MMA, a lot of people tune in who wouldn’t pay any attention to us otherwise.”

Rousey defends her belt against fellow unbeaten star Cat Zingano in the main event of the pay-per-view UFC 184 on Saturday night from Staples Center in Los Angeles. Even more significantly, the penultimate fight on the card showcases the MMA debut of Holly Holm, a champion boxer expected to be Rousey’s next big rival, against veteran Raquel Pennington.