Ladies golf, that slow, dignified sport, has just been unnerved. Laura Davies of England, with the audacity of a 23-year-old, a wave of her air travel card and a flourish of her magnificent 260-yard driver, appears to be playing something entirely different.

JoAnne Carner was one, Nancy Lopez another, women who were instantly obvious talents and went on to dominate the game thoroughly. When Davies, in only her fourth U.S. tournament appearance, won the U.S. Women's Open at Plainfield Country Club last week, the signs of a potentially rival ability were unmistakable.

Davies defeated Carner and 36-year-old Ayako Okamoto of Japan in an 18-hole playoff last Tuesday, and then flew directly to England, where she was forced to tee off in the Ladies British Open at St. Mellion in Cornwall without so much as a practice round. Davies is defending last year's title, which, with the U.S. Open, makes her the first woman in history to win both.

She held a two-shot lead after the second round, but dropped to two strokes off the pace of leader Muffin Spencer-Devlin after yesterday's third round. Should Davies win again in Cornwall, it would mean two national championships in the space of a week.

In the process, she is capturing the imaginations of pros and spectators alike. At 5 feet 10 and perhaps more than 180 pounds (she won't say), Davies appears to be the first woman golfer who is able to hit the ball like a man: She averages with her driver roughly what the men on the PGA Tour do. At the Open, she blistered one drive 276 yards. While other women might hit a 6-iron on a particular shot, she is hitting an 8.

Frank Hannigan, the U.S. Golf Association executive director, called her "the longest hitter I've ever seen in women's golf" and compared her to Carner in her early years. Carner herself was outdriven by 40 yards on some holes. Asked how she thought Davies would fare on the U.S. tour, she replied, "I think she'll have to hit all irons."

There have been fluky, first-time winners of the Open before. But Davies does not appear to be one of those.

Added to her physical ability is the fact that Davies is extremely well spoken, with a natural ease and enjoyment of being the center of attention that should make her an extremely popular star to U.S. audiences, who will get a kick out of hearing her use words like "shan't."

If not the most glamorous of young players, she has other qualities to make up for it. She has a baby-faced appeal, and her baggy sweatshirts to conceal the size she is so self-conscious of ("It's a secret") have already become something of a trademark. She is also a level-headed woman who is trying hard not to make too much of the Open, while everyone else is saying it's the first of many.

"Other people may think I should go out and win every tournament," she said. "But I shan't be going out to be the best golfer in the world. You've got to be realistic. Golf's not that kind of a game you can win week in and week out."

First, Davies will have to qualify to play the LPGA Tour. Because the Open is a USGA event, she does not receive an automatic exemption with her victory. But the LPGA has taken the matter into consideration and may give her one, anyway. She will try to play about 15 events in 1988, and how she fares over here seems a forgone conclusion to everyone but Davies.

"I'll certainly get out there and play the game," she said. "I've never played it safe. But how I'll fare against the best fields in the world, I don't really know."

But if nothing else, Davies' appalling length should make her famous for the duration. She learned it by playing with brother Tony, 26, who caddied for her at the Open. She began by walking with him and his friends through their rounds on the golf courses near their home in Ottershaw in Surrey. Eventually, she was playing whole rounds, and began trying to outdrive him.

"We would bet to see who could hit it longest on each hole, " she said.

Davies also learned to have a temper on the golf course, according to Tony, a seven-handicap who works for a seat-belt manufacturer in England. She wasn't a club thrower, but she had an uneven streak that for a while made her as likely to shoot 80 as 66. That is one difference in the last year. With a steadier temperament, she has won five tournaments overseas, including the British and Spanish Opens, and has played for the Curtis Cup team.

"She had a temper," he said. "That part of her game is improved; she's calmed down a lot."

Davies claims the temper arose more out of competition with her brother than anything else. Told of his assessment, she shot back, "Yeah, so did he. Losing to your brother is the worst thing you can do, because he gloats. So did I."

Length is not her only attribute. So is her aggressive nature. Davies plays the game with an enviable lack of responsibility. Like Lopez before her and Jane Geddes more recently, she has the ability to ignore the consequences of her shots, and the thought that she might hit a bad one seems to rarely occur to her.

Evidence of her confidence was shown at the Open when she let Tony, whom she considers a better putter, read the greens for her. He would point out a target to aim at like an umbrella, she would twitch the club once or twice, and boldly hit the putt. Usually, it went in.

It is the sort of heart-attack golf that is usually only played by extreme youths and ruthless champions. She is impervious to rough, sand and downhill lies. Her drives are gorgeous straight rockets and her swing is an impressive full cut at the ball. On the final day at Plainfield, she came to the par-5 17th with a two-stroke lead. She chose not to play it safe, going for the green in 2 and reaching it, the only woman all week to do so.

"She played good, smart golf," Carner said. "The thing I love, though, is that she just stands right up there and hits it. If she has a chance to go for it, she does. She attacks."

But Davies readily admits that she does not yet know what it all means. As for what the Open might do for her, she simply shrugged. "It's marvelous," she said. "Obviously, the first one is the sweetest."