Margaret Osborne duPont, a tenacious and durable U.S. tennis champion who won six Grand Slam singles titles in the middle decades of the 20th century while becoming one of the most dominant doubles players of her era, died Wednesday at her home in El Paso, Texas. She was 94.
Her death was confirmed by Leigh Bloss, the son of the former tennis, badminton and squash star Margaret Varner Bloss, a friend and business partner of Ms. duPont's who lived with her for much of her life.
A fixture in women's tennis for almost a quarter century, Ms. duPont won 37 Grand Slam titles, 31 of them in doubles play, placing her fourth on the list of players with the most Grand Slam laurels. Her last, in mixed doubles at Wimbledon in 1962, came at the age of 44.
Ms. duPont was ranked No. 1 in the world among women at year's end from 1947 through 1950 and among the top 10 U.S. women in the sport for the better part of 20 years, starting as an already cosmopolitan 20-year-old in San Francisco and still holding steady among the elite at 40.
It was a celebrated run of endurance and high-caliber play by a competitor who was renowned for refusing to wilt under pressure. When she lost, it was rarely in straight sets. Several of her matches set longevity records.
One was in 1948, at the U.S. national championships at Forest Hills in New York City. Over two days, she and Bill Talbert outlasted Gussie Moran and Bob Falkenberg in an epic 71-game mixed doubles semifinal, a record that stood for more than 40 years. In the same tournament, vying for the singles title, Ms. duPont came from behind to defeat Louise Brough, her friend and doubles partner, in 48 games, winning the last set, 15-13. It was the longest women's final at Forest Hills.
A poised and canny playmaker, Ms. duPont wielded a dazzling arsenal of shots, including low-flying spin volleys and gravity-defying lobs, often executed in sensible shorts rather than the billowy tennis skirts customary in her day.
She interrupted her career only twice: in 1947, to become, at 29, the second wife of William duPont Jr., a 51-year-old tennis-loving, fox hunting heir to the chemical company fortune; and in 1952, to give birth to their son, William III.
She had met her husband in California, where on yearly visits he liked to watch and play tennis.
She lived in splendor at Bellevue Hall, her husband's Delaware estate outside Wilmington, socializing with the rich and famous and practicing her game on the grounds.
Ms. duPont's concession to becoming a wife was a career-long absence from the Australian Championships, held in the winter. Her husband, an otherwise enthusiastic supporter of her career, insisted on wintering in California for his health and threatened divorce if she went to Australia, she said. Many believe she would have exceeded Billie Jean King's 39 Slam titles if she had competed in Australia. (Margaret Court had 62, the record.)
The couple did divorce, amicably, in 1964, and Ms. duPont lived for the rest of her life in Texas with Ms. Bloss, who survives her, as do Ms. duPont's son, William, a former owner of the Orlando Magic, and four grandchildren.
Margaret Evelyn Osborne was born on March 4, 1918, in Joseph, Ore., the daughter of St. Lawrence and Eva Jane Osborne. She spent her earliest years on a modest ranch tended by her parents, riding to and from school on horseback and playing baseball with her brother on a backyard lot.
Margaret began playing tennis at 9 after the family moved to Spokane, Wash., her father having been unable to continue to do farm labor for health reasons. Two years later they moved to San Francisco, where her father found work as a car mechanic. Margaret, at 11, began playing at the Golden Gate public courts, competing in tournaments and writing freelance articles for American Lawn Tennis Magazine.
After graduating from high school in 1936, and unable to afford college, Ms. duPont decided on a tennis career, starting at 18 by taking the train to Philadelphia and winning the junior nationals singles and double titles and training for a year with the renowned coach Tom Stow.
She also found work writing and working for the Northern California Tennis Association as its secretary-treasurer, and during World War II she worked in a marine shipbuilding plant.
Ms. duPont was inducted into the International Tennis Hall of Fame in 1967 alongside Bobby Riggs, Brough and Talbert, with whom she won a record four consecutive U.S. mixed doubles championships, from 1943-46.