As a harpist gently makes the music of angels, Billie Jean King touched a shot so softly it whispered against her racket strings. Only she does this so prettily, and everyone at Centre Court today recognized the genius of the little shot rising over the net, soon to fall to earth before Chris Evert Lloyd could reach it.

Or would it?

From 35 feet away, here came Evert at a sprint. With such shots born of guile and done with a virtuoso's elan, King was reborn here this week, becoming at 38 the oldest semifinalist in 62 Wimbledon summers. But this time Evert came on the fly, giving away nothing to the old champ, and she flipped a stretching forehand past King, who could only stand and watch.

The point seemed small then, only one in a hundred needed to win, but it said everything. The crafty young champ will beat the crafty old champ every time. Evert beat King, 7-6, 2-6, 6-3, and now, at 27, plays Saturday for the championship against favored Martina Navratilova, who hasn't a lost a set in the fortnight (today's victim: Bettina Bunge, 6-2, 6-2).

John McEnroe lost a set today, his first, before wiping out South African Johan Kriek, 4-6, 6-2, 7-5, 6-3. McEnroe's semifinal opponent Saturday will be Tim Mayotte, the 1981 NCAA champion who today beat Brian Teacher, 6-7, 7-6, 7-5, 3-6, 6-1. The other semifinal Saturday sends Jimmy Connors against Mark Edmondson.

Whatever happens, this is King's Wimbledon. "It might mean something to the golden oldies," King said. "It's great that someone my age is playing the youngsters. Me, I don't think it's a big deal." Memory won't recall this as the Wimbledon anyone won; it will be the summer a golden oldie made sweet music one more time, reaching the semifinals for the first time since she won her sixth singles title in 1975.

In defeat, King played superbly. Her big serve troubled Evert early. Her astonishing work at the net, the foundation that long ago made her the best woman grass court player ever, kept her close on a day when Evert, as always, was eerily accurate with passing shots.

"I'm upset that I lost," King said. "I'm proud I gave a full effort, but I didn't like the end result. Chris played well."

Without a pause, King added, "She had to."

Three times a Wimbledon champion, Evert did, in fact, need all her considerable resources.

King would play serve and volley, always attacking, while Evert would be her metronomic self, swinging ground strokes to and fro. Evert knew she couldn't lure King into a ground-stroke game and so she had to be smart enough to keep King back, patient enough to give away volleys without losing confidence, and precise enough to find open space for passing shots.

She was all of that. In the final set, Evert struck 15 of the guided-missile passing shots that were her primary weapons against King, who did two hours of sentry duty at the net. Three times Evert scored with lobs, including the last point when King took a reflexive step in pursuit only to give it up as hopeless.

"I didn't know if Billie Jean could keep up the kind of tennis she played against Tracy," Evert said, alluding to King's upset victory over third-seeded Tracy Austin two days before. "But I didn't want to underestimate her just because of her age . . . I'd forgotten how tough her first serve is. It's one of the toughest, with so much spin on it. It's difficult to hit good passing shots off it.

"The pressure was on me because I had to go with passing shots," Evert said. "Billie Jean played very well . . . Wimbledon is very sentimental and very special for her. She always plays her best here."

With one service break each, King and Evert went to a tie breaker in the first set. Evert's forehand to the corner gave her a 3-2 lead; King's error off an Evert backhand made it 4-2, and the lead rose to 5-2 when Evert hammered an irretrievable backhand at King at the net.

Evert closed out the tie breaker at 7-4 with a running forehand lob that King, trying an overhead, slammed into the net.

"A big overhead," King said later.

She won the second set easily after first breaking Evert's serve for a 3-2 lead. In a game that went to four deuces, with Evert having four game points, King hit three straight volleys for her first ad. The last, a typical King creation of inspired improvisation, was a backhand drop volley that died before even Evert could scoop it up. Then King won with a backhand passing shot.

From there King won the next three games, and went into another third set. Against Austin, she won the third, 6-2.

Evert remembered. "The first game of the third set, on my serve, was vital," she said. "Billie Jean ran off to a 3-love lead on Tracy."

With two backhand passing shots and two serves that King couldn't handle, Evert won that vital first game in two minutes. Whatever momentum King might have had was put off, and then it was ended in the second game.

Remember that soft little shot that King tried to drop at Evert's feet, only one point in a hundred needed to win? It came as the first point of the second game of the last set. Winning it with her sprint and delicate retrieval, Evert then added a forehand passing shot, a strong backhand off the frame of King's racket and, uncharacteristically, a forehand volley down the line.

At love, Evert had broken King for a 2-0 lead in the last set.

It came to match point on King's serve with Evert up, 5-2. An Evert backhand landed an inch out.

As King set up to serve at deuce, it began to rain.

"What!?!" King shouted as rain fell from a sky that a minute earlier was sunshiny bright.

Forty-one minutes later, play resumed. King worked out of that jam, staving off three match points, but Evert quickly moved to match point on her serve. A wonderful retrieval of another soft little shot--this followed by a backhand sizzling cross court past the frozen King--moved Evert to pump her fist in eager celebration of this marvel she had done.

Afterward, someone asked Evert if she'd heard that Princess Diana might attend the Saturday final. "She's a big fan of yours," a British newspaperman said.

Retrieving this one as well, Evert laughed and said, "I'm a big fan of hers, too."