Pauline Betz Addie, one of the preeminent tennis players of the 1940s, whose career came to an abrupt halt after she won four U.S. Open titles and the 1946 women’s singles championship at Wimbledon, died May 31 at the Summerville assisted-living facility in Potomac. She was 91 and had Parkinson’s disease.

Mrs. Addie, who was known by her maiden name during most of her tennis career, was the country’s dominant female player throughout World War II, when women’s tennis rose to new heights of popularity.

For six years running, 1941 through 1946, she reached the final round of the U.S. Open — then called the U.S. National Championship — and won four times. She was the top-rated player in the country.

In 1946, the only year she played at Wimbledon, she won the women’s title without losing a set in the entire tournament, defeating fellow American Louise Brough in the final. In September that year, the week she won her fourth U.S. Open, Mrs. Addie appeared on the cover of Time magazine, which pronounced her “the first lady of tennis.”

Tennis great Jack Kramer wrote in his autobiography that Mrs. Addie was the second-best female player he ever saw, after only Helen Wills Moody, who won 19 Grand Slam titles in the 1920s and 1930s. Mrs. Addie possessed a powerful backhand and remarkable speed on the court.

“I can’t believe any woman who ever lived could keep up with Pauline Betz,” Kramer wrote. “On the court she was the best athlete I ever saw in women’s tennis.”

She was the reigning Wimbledon and U.S. Open champion in 1947 and at the peak of her athletic powers, but she would never appear in a major tournament again. When it was learned that she had explored the possibility of turning professional, she was banned from amateur competition because of “intent” and was not allowed to defend her championships.

Professional players were not allowed to participate in the four major Grand Slam events — Wimbledon and the U.S., French and Australian opens — until 1968. This year, the men’s and women’s champions at Wimbledon will receive $1.8 million apiece.

But when Mrs. Addie competed during the wooden-racket era, the code of amateurism was so strictly enforced that the world’s most prestigious tennis tournaments awarded no prize money.

“I remember that even after I’d already won the nationals I was still working as a waitress,” Mrs. Addie told the Washington City Paper in 2005. “That’s just the way things were.”

Cast adrift from the leading showcases of her sport, Mrs. Addie embarked on a peripatetic professional career, touring the country from 1947 to 1951 with men’s stars Kramer, Bobby Riggs and Pancho Segura. She was most often matched with “Gorgeous” Gussie Moran, who had scandalized the tennis world in the late 1940s when her tennis skirt rose up to reveal lace-trimmed underwear.

Mrs. Addie defeated Moran so often in their exhibition matches that she was told to take it easy.

“I wasn’t about to let them cancel the tour,” she said in 2005. “So let’s just say Gussie Moran got better all of a sudden, and the tour continued. I studied economics in college.”

Pauline May Betz was born Aug. 6, 1919, in Dayton, Ohio, and grew up in Los Angeles. Her mother, a physical education teacher, introduced her to tennis at age 9. She won tournaments throughout California in her teens and won a scholarship to Rollins College in Winter Park, Fla., from which she graduated in 1943.

Mrs. Addie won the U.S. Open title from 1942 through 1944 and again in 1946. In addition to her Wimbledon championship, she won the mixed doubles competition at the 1946 French Open.

She was followed by gossip columnists, who chronicled her friendships with actors Katharine Hepburn and Spencer Tracy, boxer Jack Dempsey and heiress Barbara Hutton.

In 1949, she married Bob Addie, a sportswriter for the old Washington Times-Herald and later The Washington Post. She became the teaching pro at the Edgemoor tennis club in Bethesda and continued to compete as a professional.

She won seven women’s professional championships before losing in a grueling 2 ½ -hour match to Althea Gibson in 1960. Mrs. Addie was a 40-year-old mother of five at the time, and Gibson — the first African American tennis star – was just two years removed from winning Wimbledon and the U.S. Open.

“I beat her after that in a tournament in Hampton, Va.,” Mrs. Addie told The Post in 1965. “So I figure we came out even.”

Mrs. Addie, who played tennis into her 80s, ran a tennis camp at the Sidwell Friends School in the District and taught for 20 years in Bethesda at what is now the Pauline Betz Addie Tennis Center. She was inducted into the International Tennis Hall of Fame in 1965.

Mrs. Addie’s husband died in 1982. Survivors include their children, Rusty Addie of Bethesda, John Addie of Avon Park, Fla., Kim Addonizio of Oakland, Calif., Gary Addie of Washington and Rick Addie of Aldie, Va.; a brother; five grandchildren; and a great-grandson.

Mrs. Addie’s sense of competitiveness extended to other sports, including golf, basketball and table tennis. Later in life, she became a tournament bridge player at the life master level.

She played the piano and flute and once took a course in car mechanics to learn how to take apart an engine.

Soon after she met her future husband, her son Gary recalled, she lost $50 to him in a poker game. She wrote a check for the full amount but signed her name “Pauline Betz Addie.”

“If you want to collect,” she said as she handed over the check, “you’ll have to marry me.”