This was Ali dancing one last time in Zaire, this was Hogan throwing a 30 at Augusta in the sunset, this was Howe putting a kid into the boards. This was Billie Jean King rallying to beat a teen-ager who in the fifth grade got an A minus for a theme on BJK's long career.

King is 38 and gimpy, Tracy Austin 19 and bouncy. Where King has been, Austin will go. But not right away. King beat the third-seeded Austin today, 3-6, 6-4, 6-2, on the Centre Court where she made her Wimbledon debut in 1961, a year and a half before Austin was born.

Six times Wimbledon champion, five times in for surgery on her knees, once "retired," King confounded Austin with an array of soft shots craftily conceived and artfully executed.

The old conniver did everything with the ball but scratch it on her belt buckle. Dinks, loops, backspins, topspins--even a drop volley from eight feet up that may have been luck, or may have been inspired.

"Garbage," King called the soft stuff. Whatever it was, it lost only five points as it won four straight games--the last game of the second set, the crushing first three of the last--and put King in the semifinals for the first time since her last title, in 1975.

And finally this Wimbledon is memorable. Another day's forgettable work for top-seeded Martina Navratilova and No. 2 Chris Evert Lloyd moved them into Friday's semifinals. Evert plays King and Navratilova faces the winner of Thursday's Anne Smith-Bettina Bunge match.

The men have been a bore. John McEnroe and Jimmy Connors won again in straight-set ease. Vitas Gerulaitis (the third seed) beat Roscoe Tanner in straight sets. Only the No. 4 seed, Sandy Mayer, failed expectations, botching a two-set lead over Tim Mayotte.

Thank heaven for old ladies. As so many Wimbledons have been, we now have one made by King. She had never beaten Austin, losing five times, only twice winning a set. They last played in 1980; they first played in the quarterfinals of Wimbledon in 1979.

King remembered that first time today.

"I looked at the scoreboard when I was up, 2-0, in the third set," King said, "and the number 2 kept getting bigger and bigger and bigger. I said, 'If I don't win this next game and see a 3, I'm gonna . . . "

Three summers ago, after leading, 2-0, in the third set, King crumbled before the 16-year-old kid. Everyone wrote her tennis obituary. The order had changed. No one with five knee operations, no one nearer 40 than 30, no one who won her first Wimbledon in 1966--no such old lady could stop the march of the pigtailed killers begun by Evert and continuing with Austin.

King gave in to middle age last year. She needs to weigh 130 to play tennis; chocolate bars moved her to 160. One day she discovered herself playing "hit and giggle tennis" with her husband. Hogan doesn't putt at windmills next to shopping centers, and King couldn't hit and giggle for long.

So she started running again and cut out the candy bars. She played more this year--eight tournaments, winning a minor-league event in England this month--and came to Wimbledon not for a nostalgia fix but to win.

After surviving triple match point in her second match, King, seeded 12th out of respect for the name, upset sixth-seeded Wendy Turnbull in decisive straight sets and came to Centre Court against Austin with no worries.

"I felt calm, it's great to be here," King said of her record 104th singles match at Wimbledon. Winning for the 91st time and getting to the semifinals for the 13th time, King built today's 2-0 lead in the third set with a half-hour's play that might have come from the book BJK advises every young player to read: Bill Tilden's "Match Play and the Spin of the Ball."

The match turned, in fact, when King broke Austin's serve at 15 for a 5-2 lead in the second set. Moving Austin from corner to corner and keeping her deep with the sliced backhands that made King the youngster nigh invincible, King the old conniver yet sent a hard forehand down the line the only time Austin dared to come to net.

"That was a very big point," she said of the forehand that made it 15-40. "I just hit it--BOOM!--and, 'My goodness, it's going in!' "

Then a nifty forehand volley sent Austin scuttling back to the far corner, from where she could do nothing.

After King held serve at love to win the second set, she immediately broke Austin in the third.

First, a backhand volley. An overhead into the net made it 15-all. Austin's long forehand made it 15-30, then King's running forehand down the line and Austin's winning backhand to the corner made it 30-40.

A soft forehand by King down the middle sat up for Austin, whose strong forehand seemed past King at the net. But with a lunging backhand volley, King deftly angled a shot cross court.

King then held serve to put the "2" on the scoreboard. Would there be a "3" this time?

It took about three minutes. King broke Austin a second time. She gained an ad with a backhand volley after a marvelous forehand get of Austin's smash down the line, and caused the "3" to go up with a forehand volley.

Austin was inconsistent with ground strokes all day, which she attributed to the back injury that has limited her work. She also said she went to bed last night at 6:30 with a fever. "I sweated through three sweat suits," she said, right after saying she wasn't making excuses.

On match point, an overhead, King raised her arms in triumph and later held her racket high in answer to the standing ovation from 14,000 Centre Court customers. She curtsied to the Duchess of Kent on the way out, then gave one last wave before disappearing.

"Billie Jean played well," a teary Austin said afterward. "It was no miracle or anything . . . She's had enough experience to know what to do. She's a really smart lady . . . She thinks about tennis 23 hours a day, which is great, and that's why she can keep in it so long."

It was "something special that she had never beaten me," Austin said. "So I'm really disappointed, much more disappointed than last year. I felt I had a better chance this year."

Austin said she first really thought about Billie Jean in the fifth grade.

"We had to do a composition on a famous person, and I did mine on Billie Jean. I got an A minus. I was mad, because I had pictures and everything."

At that time, Billie Jean King had won five Wimbledons. She was 30 years old and everyone said she ought to quit before she needed another operation on her knees.