Equal pay for women is one of the most pressing issues in American sports today. Just last year, U.S. Soccer finally announced it will pay the wildly successful women’s national team the same as it does the men’s team. Most national governing bodies of U.S. Olympic sports pay women and men equally, although the U.S. Golf Association doesn’t at its U.S. Opens, nor do many of our pro sports, golf and basketball among them.

But tennis? That’s quite another story, and an uplifting one. The U.S. Tennis Association has been paying women the same prize money as men at the U.S. Open for 50 years.

Yes, 50 years. The U.S. Open started paying women the same as men back in 1973. For a comparison just within the sport of tennis, the Australian Open didn’t get around to equal prize money until the next century, 2001, while the French Open and Wimbledon dithered until 2006 and 2007, respectively.

How did the USTA get so far ahead of everyone else?

“It was a lot of hard work,” said the person who was doing most of it, tennis legend Billie Jean King.

In an interview with USA TODAY Sports, King said the idea of fighting for equal pay at the 1973 U.S. Open popped into her head during her winning press conference the year before.

EQUAL PAY: USWNT's fight for equal pay is an accomplishment for all women

“In 1972, I won and got $10,000, while the men’s champion, Ilie Nastase, won and got $25,000,” she said over the phone Monday afternoon. “This was ridiculous so I said, ‘I don’t think the women are going to be back next year, we’re not going to be back in 1973 unless we get equal prize money.’ I’m saying this but just hoping and trusting the other players would go along with it at that point.”

King was the part-owner of a couple of tournaments and felt comfortable within the business side of her sport, so she had an idea.

“I knew I had to not just complain, but to come up with solutions,” she said, “so I talked to different sponsors and asked them if they’d make up the difference in total prize money. I was a business woman and this was a business decision, so I knew if I got some sponsors to pay more money, I was hoping that would make the difference, and it did.”

At the 1973 U.S. Open, the male and female champion each received $25,000.

It’s fitting to discuss this topic today of all days: March 14, the day dubbed “Equal Pay Day” by the National Committee on Pay Equity. It’s the day that symbolizes how far into the new year women must work to earn what men earned by Dec. 31 last year. It’s also the day, nearly halfway through Women’s History Month, that the USTA has chosen to announce that a celebration of equity and the 50th anniversary of equal prize money will be the theme of the 2023 U.S. Open, accompanied by very ‘70s artwork celebrating King.

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The USTA also is supporting a campaign to award King the Congressional Gold Medal. Eleven individual male athletes and the 1980 U.S. Summer Olympic team that was not able to compete due to the nation’s boycott of the Moscow Games have received the honor. No individual female athlete has won the medal.

“The campaign is directed towards members of Congress who ultimately make the decision,” said USTA spokesman Chris Widmaier. “Who better than Billie to be considered this year?”

Said King, “I was surprised an individual sportswoman hasn’t gotten it. If I can kick it off so they think about other women, that’s great.”

The year 1973 was a big one for women in sports. In addition to equal pay at the U.S. Open, the Women’s Tennis Association was founded in June 1973 by King, one of nine players who comprised the WTA, also referred to as the Original 9.

It also was the year of King’s famous straight-sets victory over self-described male chauvinist Bobby Riggs in the “Battle of the Sexes” in front of millions on primetime national TV on Sept. 20, 1973. Needless to say, the 50th anniversary of that event will not go unnoticed.

“I thought maybe we would go away if I didn’t beat Bobby,” she said. “Title IX had just passed the year before, and I was worried women’s sports would be in trouble if I didn’t win. I knew people would be making bets, husbands and wives, sororities and fraternities. It was that big of a deal and all these years later, people still come up to me to tell me what it meant to them.”

With so many anniversaries on the horizon, King acknowledged she “probably is appreciating all of it for the first time ever. Back then, there always was more to do, so I just kept going.”

Which explains the first word she thinks of when recalling 1973.

“Tired is my first word,” she said. “It was a huge year, a pivotal year for tennis and for women in general. I just remember being exhausted all the time. As I’ve said before, when I sleep in now, I’m still catching up from the 1970s.”

Editor's note: In 2008, USA TODAY Sports columnist Christine Brennan co-authored the book "Pressure is a Privilege," with Billie Jean King.

This article originally appeared on USA TODAY: Billie Jean King made sure USTA led the way on equal pay 50 years ago