Celebrating both the 40th anniversary of equal prize money for men's and women's players at the US Open and the formation of the Women's Tennis Association, founded in 1973, USOpen.org is proud to present "40 Important Women's Moments in US Open History."

This look at some of the greatest achievements and accomplishments by women players from the last 40 years will run all the way to the 2013 US Open women's singles final, scheduled for Sunday, Sept. 8. To review our entire countdown of the 40 Important Women's Moments in US Open History, click here.

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THE BUZZ: The US Open becomes the first Grand Slam event to offer equal prize money for both the men’s and women’s events, with two-time defending US Open champ Billie Jean King and the newly formed WTA lobbying for change.

THE IMPACT: American sports were not immune from the swell of social evolution taking place in the country – civil rights and women’s rights movements born of the radical 1960s had grown in strength and developed into more educated enterprises by the early 1970s, preaching inclusion. Title IX, the educational amendment that protected women against discrimination in school and in the workplace, and which required athletic departments in American schools to offer tennis programs in proportion to gender population, went into effect in 1972.

The United States was moving forward. So too was the US Open, with the summer of 1973 the launching point that made tennis stars like Billie Jean King, Chris Evert and Martina Navratilova into household names. In three months’ time, tennis would change forever. Here’s a brief breakdown:

• On June 20, the Women’s Tennis Association was founded at a meeting of more than 60 women’s players, organized by King at the Gloucester Hotel in London before Wimbledon. More and more women had become professionals with the advent of the Open era five years earlier in 1968, and they were fighting to make a living.

Included in this gathering were “The Original Nine,” as they were called, the women who signed contracts to play in the Virginia Slims Series three years prior, the first women’s professional tour: Then-two-time defending US Open singles champ King, past Open women’s doubles winners Rosemary Casals, Nancy Richey and Judy Dalton, Kerry Melville, Peaches Bartkowicz, Valerie Ziegenfuss and Julie Heldman.

Stacey Allaster, the current chairwoman and chief executive of the WTA, told The New York Times in an August 2013 interview: “If we had not had Billie, I’m not sure we’d be the success we are today.”

• Less than a month later, on July 19, after lobbying efforts from King that included the recruitment of sponsors to supplement player pay to make the men’s and women’s purses the same, US Open Tournament Director Billy Talbert announces that New York would be the first Grand Slam event to offer equal prize money to women and men.

“I really am thrilled, as a U.S. citizen, that we were the first,” said King.

It would be nearly 30 years before the next major would institute the practice. The Australian Open introduced equal prize money in 2001, with Roland Garros and Wimbledon to follow in 2007.

• Then on Sept. 20, just 12 days after Margaret Court collected the same $25,000 paycheck as fellow Australian John Newcombe for winning the Open, King defeated bombastic men’s player Bobby Riggs in the “Battle of the Sexes” exhibition as 30,472 fans watched inside Houston’s Astrodome, 6-4, 6-3, 6-3.

Given how the match would be viewed in historical context thereafter, it’s fitting that the attendance figure remains the largest live audience to see a tennis match in the U.S.

“Men come up to me in their 40s and 50s today, a lot of times with tears in their eyes, and they say how much that match changed their whole perception, how they have a daughter and how they're going to raise her,” said King. “That they insist that their boys and girls, their sons and daughters, have equal opportunity. … President [Barack] Obama was 12 years old when I played that, and he’s told me the story, too.”

A recent report by Forbes magazine revealing the world’s highest-paid female athletes ranks tennis players No. 1 thorough No. 4, and seven of the Top 10 women overall. From June 2012 to June 2013, defending US Open champion Serena Williams earned $8.5 million in prize money. World No. 3 Maria Sharapova claimed $6 million in prizes and $29 million overall when factoring in endorsements to come in as the highest earner.

“It's really exciting for me to have an opportunity to play for equal prize money,” said Williams before the tournament began. “And thanks to people like Billie Jean King and The Original 9 that started [the WTA], that sat down and said: ‘You know, we want equal prize money. This is what we're going to do.’ It feels really good.”

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So concludes “40 Important Women’s Moments in US Open History.” Beginning with this year’s US Open, here’s to the next 40 years of special memories. Past, present and future considered, the women’s game should be on the upswing for a long time to come.

THE QUESTION: Where do you see women’s tennis heading in the next 40 years?