By Liza Horan

New York—Jelena Jankovic and Tracy Austin hit two tennis birthday parties in two days: The Women’s Tennis Association marked its 35th on the eve of the U.S. Open, and center court festivities featured lots of past champions celebrating the 40th anniversary of the Open Era.

About the 35th anniversary of the WTA: The players’ union was founded when Billie Jean King and others signed a contract (worth $1 per player) to compete at tournaments. The union paved the way for a career as a professional.

The party: The milestone of 35 years was feted at the Sports Museum of America, which opened in May just across of famed Wall Street bronze bull statue downtown, in a party given by the U.S. Tennis Associationand sponsored by TENNIS Magazine. The event doubled as a fundraiser benefiting the Billie Jean King International Women's Sports Center, part of the Women's Sports Foundation, which is dedicated to equal play and inspiring girls to be active and play sports.

Jankovic (above right), who relishes the red carpet, gushed about the full-length, black and white printed gown by Roberto Cavalli. Savory bites, bubbly drinks and even Sugar Daddy pops—bringing back memories of King's 1973 Battle of the Sexes victory over Bobby Riggs—were among the refreshments that preceded a top-notch presentation.

Highlight: “It’s something different for me. I’m used to wearing clothes with curves and this is flowy,” said the No. 2 seed. “This is very comfortable. I love dressing up and I love looking feminine and elegant.”

The Serb has managed to bring that sensibility to her work wardrobe by Reebok, as well. She’s sporting a yellow gauze-like sheer top, over a white shirt and skirt, that billows when she’s still yet moves with her when she delivers razor-sharp groundies.

When players like King signed that first contract to play 35 years ago, none of them were wearing designer duds. In fact, King says she taped her bust to minimize movement during play. Now professional tennis means fashion, fame, a worldwide stage, business and big money.

Women’s tennis has come a long way, baby, as the WTA’s youngest U.S. Open champ, Austin, can testify.

“I think every year they are getting better. As any organization does, you look at your strengths, your weaknesses, where you want to go and you work to improve.

“I was the first 14-year-old to come on and I would have loved to have had a mentor. Now, they have that. Each year everything gets better—the physio, the training, the schedule.”

About the 40th anniversary of Open tennis: Forty-one years ago the national championships were playable only by professionals; you had to be invited, and amateurs weren’t allowed. That changed in 1968 as amateur Arthur Ashe won the men’s tournament over pro Tom Okker, who collected both the winner’s and the finalist’s prize money. Virginia Wade collected $6,000 in her victory over Billie Jean King.

The party: About 20,000 people were in Arthur Ashe Stadium for the opening night fireworks and entertainment marking the 40th anniversary of open play. Wade was among the past U.S. Open champions—Monica Seles, Boris Becker, Marat Safin, Andy Roddick, Martina Navratilova, Chris Evert, and Ashe’s widow Jeanne Moutoussamy-Ashe and daughter Camera, plus many others—who processed on court, waving to fans.

Highlight: John McEnroe and Roger Federer received the loudest applause, but it was four-time champ Federer who got the only standing ovation. New York respects a winner, cherishes a character, and loves an underdog. If the crowd’s response was a popularity meter, the Swiss won it hands-down. The past champs took a victory lap (walking, not running) around the court so Earth, Wind & Fire could take the stage and burst into song. The show was followed by Jankovic’s dismantling of up-and-coming American Coco Vandeweghe, and the stellar five-setter between James Blake and Donald Young.

The first night of the Open didn’t get subway-riding fans back to Manhattan ‘til about 2 a.m. What a way to start the fortnight.