Chris Evert, playing what she called "the best match I could possibly play on grass," crushed Billie Jean King, 6-1, 6-2, in the quarterfinals of Wimbledon today.

Evert, defending champion and No. 1 seed, did all her damage in only 43 minutes. It was the most decisive defeat ever suffered at Wimbledon by King, making a comeback in quest of her seventh singles title here.

Evert, who first won here at age 19 in 1974, will play Englishwoman Virginia Wade, one of the two players who have beaten her in tournaments the year, in Wednesday's semifinals.

Wade, 31, more relaxed and determined than ever before as she strives to win her national title in Wimbledon's centenary year, was impressive in defeating Rosemary Casals, 7-5, 6-2.

No 2 seed Martina Navratilova, the other player to beat Evert this year, was upset by Betty Stove, 9-8, 3-6, 6-1.

Navratilova, 20, the expatriate Czech lefthander, let a 6-2 lead (quadruple set point) get away in the first set tie braker, played a dreadful third set after Stove choked away a 3-1 lead in the second, then dissolved into tears.

Stove, 32, will play the other Great British Hope 21-year-old Sue Barker, in the semifinals. Barker overcame some early center court nerves ("my arm was a bit stiff when we went out there") and fitful serving to oust Kerry Melville Reid, 6-3, 6-4.

Evert rose splendidly to what was for her a very special and stimulating occasion, against a player she long held in awe.

Although she held a 9-7 career advantage over King, she was 0-3 on grass, King's best surface; Evert's worst.

Twice before they had met on the center court, that stately and imposing emerald arean King, the dominant Wimbledon player of the postwar era, lovingly refers to as "My House." King had won with grand exhibitions of physical and mental toughess, in the 1973 final and 1975 semifinals.

Evert knew, too, that King had set Wimbledon't 100th anniversary as the beacon light of her comeback from knee surgery in November.

From the time the players strode onto the court and curtsied to the rayal box - King smiling, Evert looking so subdued as to be grim - Evert meant business. "Chrissie has The Look" noted one spectator in the competitor's section. Indeed she did.

Evert served well and kept ferocious pressure on King's serves with returns that were hard, deep and varied. Her ground strokes were punishing as ever.

She came to the net to dig out drop shots and didn't miss a volley. She "read" King flawlessly, anticipating every stroke and answering it with the voice of authority.

Evert's magnificent shotmaking and King's apparent lack of the mental and technical sharpness that comes from having played numerous rugged matches recently quickly took the suspense out of what had promised to be a fine match.

By the time Evert built a 5-0 lead in the first set, the outcome no longer seemed in doubt. The question was whether or not Billie Jean would be able to avert her most lopsided defeat here - 6-3, 6-1, to Ann Haydon in the quarterfinals of 1962, when she was 18.

She didn't.

"I was really in control. I felt I could do almost anything out there," she said. "My passing shots were particularly good. I've never really played that consistently well. Billie was serving and I was passing her off both sides; down-the-line and crosscourt.

"I think the most important thing was that she didn't intimidate me . . . just the name Billie Jean and the fact I'd never beaten her on grass before, I was not super-confident going into the match. But I was eager, probably more eager than any other match I've had lately.

"It was a challenge for me, and these days it's hard for me to find new challenges in tennis. She's the best on grass. Her record shows it. My game is still not suited to grass and I don't feel 100 per cent confident on it. But today I didn't feel intimidated by any of her shots."

King still does not have her old mobility, and on crucial points she was missing fractionally. That was too much against Evert, who hit an extraordinary number of clean winners within inches of the lines.

"In the past, I've been intimidated by Billie Jean because she's talked to herself during the match, she's always had a few comments. Today she didn't have her usual zest. I didn't see any fire in her eyes like I usually see," Evert said.

King said she was not embarrassed "I gave an honest effort, that's all I can do" - but vowed that she will be back next year. The match, she said, gave her a gauge of how far she still has to go.

"I think Chris played really beautiful tennis," she said, adding later, "I don't know if I would have been able to beat her even on my best day, the way she played today.

"I think I still have a lot of work to do. I don't feel match tough. There are two or three shots I'm not sharp on and that irritates me to death."

Can she regain the level she had?

"Mentally, I know I can; physically, I don't know," King said. "The doctor told me to give myself a year, and I can't be impatient.

"I don't think very many people would have beaten Chris today.Let's forget knees, ankles, toes, brains, whatever. She was more 'up' for the match than I was and really played well."

Wade served well and lobbed with exceptional touch in the tricky swirling breezes of No. 1 Court to beat Casals "Our Ginny," as the British newspapers extol Wade, lost the first point of the match, won 13 in a row, lost her serve at love, and then pulled of 0-40 at 5-5.

Wade raised her game just when it seemed Casals, 2-0 over her this year, might get rolling.

Barker prevailed in a match of backcourt players with potent forehands. But it was her backhand, down the line on critical points, that won her the match against Reid.

Stove, like Barker a first-time semifinalist, served an ace to finish off Navratilova after going into a nervous nosedive from 3-1 in the second set.

She won the last six points of the first set tie breaker against her good friend who gave one of those points away when Stove received a bad call. After breaking for a 2-0 lead in the second, Stove started bungling volleys and overheads, a not uncharacteristic response for her to being ahead in a match she was figured to lose.

Ultimately, Navratilova disintegrated entirely after running the last five games of the second set, and could not even keep the ball in play.

It was a dreary match; far more points were lost than won and toward the end Navratilova could hardly return a serve, even off Stone's second delivery. It was a sad exit for the talented Navratilova, who has played well this year but today was neither executing nor thinking.