40 greatest female athletes: Billie Jean King

In 1990, Life magazine named Billie Jean King one of the 100 most important Americans of the 20th century. AP Photo

ESPN is marking the 40th anniversary of Title IX by unveiling the top 40 female athletes of the past 40 years.

Billie Jean King, who spent five years as the No. 1 women's tennis player in the world, won six Wimbledon singles titles, four U.S. Open singles titles and 29 Grand Slam doubles and mixed doubles titles.

But the victory she will always be remembered for is the Battle of the Sexes against Bobby Riggs in the Houston Astrodome on Sept. 20, 1973. King, the No. 11 woman in ESPN's countdown, won handily, 6-4, 6-3, 6-3, humbling Riggs, educating men and empowering her gender.

"Billie Jean has been so influential in helping women earn more in terms of respect, prize money and other opportunities," says Pam Shriver, a 21-time Grand Slam doubles champ and now an ESPN analyst. "Think of Maria Sharapova or Li Na in China. Commercial opportunities are huge for women tennis players, but women in all sports can tip a cap to Billie Jean."

Read the full story from espnW here.

Earlier in this series:

No. 40: Diver Fu Mingxia

No. 39: Jockey Julie Krone

No. 38: Gymnast Mary Lou Retton

No. 37: Hockey player Cammi Granato

No. 36: Soccer player Kristine Lilly

No. 35: Basketball player Diana Taurasi

No 34: Volleyball player Flo Hyman

No. 33: Soccer player Abby Wambach

No. 32: Swimmer Mary T. Meagher

No. 31: Marathoner Joan Benoit

No. 30: Sprinter Gail Devers

No. 29: Basketball player Nancy Lieberman

No. 28: Marathoner Grete Waitz

No. 27: Soccer player Michelle Akers

No. 26: Basketball player Chamique Holdsclaw

No. 25: Swimmer Dara Torres

No. 24: Golfer Nancy Lopez

No. 23: Swimmer Tracy Caulkins

No. 22: Soccer player Marta Vieira da Silva

No. 21: Tennis player Venus Williams

No. 20: Figure skater Michelle Kwan

No. 19: Skier Lindsey Vonn

No. 18: Softball player Lisa Fernandez

No. 17: Basketball player Ann Meyers Drysdale

No. 16: Basketball player Sheryl Swoopes

No. 15: Swimmer Janet Evans

No. 14: Figure skater Katarina Witt

No. 13: Basketball player Cheryl Miller

No. 12: Sprinter Florence Griffith-Joyner