Billie Jean King was in the soon-to-be-demolished Wachovia Spectrum yesterday to hit a few tennis balls, for old times' sake. As might be expected, the memories came flooding back for the 65-year-old firebrand who changed the way tennis is watched and played.

"The Astrodome, I think, is going to be imploded as well," said King, recalling her straight-sets victory over Bobby Riggs in the Sept. 20, 1973, "Battle of the Sexes" that is a major part of her legacy. "You just wish these great buildings could still be a part of ongoing history, not just be history.

"It's progress. I understand it. I don't have to like it. I mean, I watched the Flyers play [in the Spectrum] in Ed Snider's superbox. I played FedEx Cup there; we beat Australia. And I played for the Freedoms in '74."

The Spectrum might not be around too much longer, but the Freedoms and World TeamTennis, which King co-founded that year, are still going strong. Which doesn't surprise King at all. When she commits herself to a project, she never believes it will be for the short term.

"This is our 34th year and the 10th year for the Freedoms - 1974 and now for the last 9 years," she said with almost parental pride.

The 3-week WTT season - which runs from July 2-26 - is reflective of King's original vision, which called for the radical makeover of a once-staid sport. WTT is, at its heart, rock 'n' roll tennis, which makes sense since "Philadelphia Freedom," which King's dear friend Elton John wrote in her honor in 1975, still gets air play on classic-rock radio stations.

Thirty-five years ago, the tennis establishment resisted the changes King sought to implement. Which, of course, made King dig in all the more.

"I hated it," she said of the way tennis once was played, as if the game belonged in cathedrals and libraries, with timid, quiet spectators almost afraid to move or make noise. King's vision for WTT was, well, a lot rowdier and fan-friendly.

"We're the first ones to have music," she said. "We're the first to have colored courts. We're the first to hit balls into the stands as souvenirs for the fans, to have the players' names on the back of the shirts."

Slowly, the old guard began to come around, as King imagined it would. The national governing body of tennis, the USTA, has a 25 percent piece of the WTT, in effect becoming a partner of its onetime nemesis.

"Regular tennis does not pretty much what we do," King said. "They used to give us a bad time. They used to try to tear us down, to make us go bye-bye. But we are in the fabric of the sport now."

The Freedoms are reflective of WTT's broad reach. Each team is composed of two men, two women and a coach. The rosters of the 10 teams include current touring pros, retired legends and up-and-comers.

Retired superstar Andre Agassi, top 10 women's player Venus Williams and 14-year-old prospect Madison Keys are the yesterday, today and tomorrow of the game for which King's passion has never ebbed.

"We like to have three generations if we can," King said. "That's always been our goal. And because we play only one set, the older players are still very competitive. John McEnroe can play a set against anybody, but he can't play three out of five sets against anybody anymore."

King is one of the winningest players, male or female, ever, with 39 Grand Slam singles, doubles and mixed-doubles titles, including a record 20 at Wimbledon. But for many, she still is best remembered for her exhibition match with Riggs that drew an on-site crowd of 30,472 and a global television audience of an estimated 55 million.

"I didn't want to play him," King recalled. "He came after me for 3 years. I said no, Chris Evert said no. But Margaret [Court] said yes, for $35,000."

Court lost and, thrust into the role of savior for the women's movement, King had no choice but to accept Riggs' challenge.

"I knew I had to play him," King said. "I would have have played him if Margaret hadn't lost. I guess you can say Margaret took one for the team."

When King defeated Riggs, 6-4, 6-3, 6-3, her feeling was not so much exultation as relief.

"Losing to Bobby was my nightmare," she said. "It would have set women back. But I think men's perceptions of us - women - really changed after that night. I think everyone came to realize that men and women, we're all people." *