Even resting her old bones in a warm bath afterward, Billie Jean King couldn't believe she had won.

"Oh, God, I didn't do it." That's what she thought in the tub, King said, her voice full of remembered woe as she added, "I have to have time to realize I'm still in the tournament."

Only one point away from a quick defeat at Wimbledon today, the six-time champion created yet another piece of dramatic theater on the Centre Court that has been her favorite stage for 20 summers. Now 38 with shining scars from five knee operations, King won in three rain-interrupted sets, 5-7, 7-6 (7-2) and 6-3, over Tanya Harford, 23 and robust.

The victory moved the 12th-seeded King into Wimbledon's round of 16, where she next faces the sixth seed, Wendy Turnbull, a straight-set winner as London's fifth day of rain in the last six put off another 100 matches until play resumes Monday.

Just ahead of darkness that stopped play today, Zina Garrison of Houston, 18, won her third straight-set victory, this time over Lucia Romanov, 6-0, 6-4, to advance to the final 16 where on Tuesday she takes her clay-court game against the tournament's overwhelming favorite, Martina Navratilova.

On the men's uninspiring side of play, third-seeded Vitas Gerulaitis, never a finalist in a Grand Slam tournament except the sinking-in-prestige Australian Open, racked up his second straight-set victory here. His blond lion's mane of curly locks flying as he whizzed to and fro, Gerulaitis zapped Bruce Derlin, 7-5, 6-2, 6-3.

"Mr. Gerulaitis has left the grounds," a press spokesman said to reporters waiting. "He has gone to a Rolling Stones concert."

Fifth-seeded Johan Kriek again struggled, following his four-set opening victory with a five-setter against Peter Elter, winning the last two sets with the loss of only four games. Great Britain's only survivor in either men's or women's play, 15th-seeded Buster Mottram, defeated Victor Amaya in four undistinguished sets.

Darkness left unseeded Chip Hooper, the rising American star and source of this Wimbledon's only electricity, dead even with Russell Simpson at 3-6, 6-1, 3-6, 7-6. Hooper won the fourth-set tie breaker, 7-2, scoring seven points in succession as daylight disappeared around his 150-mph serve.

The very breath of life in this Wimbledon was about to disappear from King in the second set of her record 101st singles match here, this against a women 15 years her junior with an unremarkable record.

Unremarkable except that in five years, while never winning and never ranked higher than 31st, she pulled off an occasional major upset. She beat Virginia Wade and Pam Shriver, and twice took Navratilova three sets.

Play was delayed at the start by rain today and then interrupted three times. Through these fits and starts, Harford built a 5-4 lead in the second set and was up love-40 on King's serve in the 10th game.

"Triple match point," someone said.

"Triple Wimbledon point," his neighbor said, knowing this may be the old champion's last trip here.

"Triple career point," another man said.

Harford then netted a forehand: 15-40.

King's overhead next made it 30-40 when Harford could only deflect it. By now, King said later, she had used her day's nostalgia fix to good purposes. During one of the rain delays, the locker room television played film of the 1972 men's final in which Stan Smith beat Ilie Nastase.

"Smith was down love-30 at 4-all when he barely got a volley back," King said. "It hit the wood at the end of the racket and just got over the net. That shot made all the difference. Then I got called to go back on court."

So when she found herself down love-40, King said she thought of the Smith comeback and reminded herself, "you never know what's going to happen . . . I said, 'See if you can hang in long. The more shots I can hit, the tide will turn in my favor.'"

Still down, 30-40, still down match point, King sent a volley down the line and seemed to hesitate as it came to earth, as if she thought it were out and the match over.

"No, when I hit it I thought it was going to go out, but the wind blew it way in," she said. Her hesitation was indecision on whether to follow the shot or not, which was cleared up in time to get her to the net where Harford's return was floating.

King was undecided again whether to let the ball bounce or take it on the fly and risk hitting the net.

"What if I'd let it bounce and it just rolled away?" she said. So she gently touched it, allowing it to fall back in Harford's territory.

Now it was deuce, and King ran out two more points with delicate touch shots Harford couldn't get back.

Not only that, King scored the first four points of the tie breaker with three block-volleys and an overhead. The die was cast, then, and most of the 7,000 customers in the half-full Centre Court stadium knew King, the heroine of so many thrillers here, had the young South African in big trouble.

Each held service through seven games of the third set, with King holding a 4-3 lead when she broke Harford at 15 in the eighth game.

King passed her with a crackling backhand to make it 30-love, made it 40-15 with a forehand down the line that Harford couldn't handle and won the game with a block volley that rushed Harford so much she hurried it wide.

Serving for the match, King again gave up only one point. And afterward, like an actress accepting an Oscar, Billie Jean King wanted to thank a lot of people.

Especially the laundry lady, named Marjorie Fraser.

King is superstitious. She wore her lucky dress today, white with blue doo-dads around the hem. Even after being rained on, she didn't want to change.

"We've got 45 minutes, Mrs. Fraser, do you think you can wash my dress and get it dry?'" King said she asked in the locker room.

Mrs. Fraser washed and dried King's outfit twice.

"Everyone here is trying to help you," King said before exiting stage left.