If Jenny Chuasiriporn had any trepidation about hitting her opening shot as a professional today in the first round of the U.S. Women's Open, it hardly showed on the first tee -- or the first nine holes, for that matter. She drilled her drive straight down the middle, made three front-side birdies and was leading at 3-under-par 33 when she made the turn.

Then reality set in at steamy Old Waverly Golf Club. On her next three holes, the Timonium, Md., native and recent Duke graduate recorded a triple bogey, double bogey and bogey. By day's end, Chuasiriporn, last year's Open runner-up as an amateur, had soared to 5-over 77, with an ugly 44 on the more difficult back nine.

That left her 13 shots behind the leader, Kelli Kuehne of Dallas. A two-time U.S. Women's Amateur champion and the younger sister of current U.S. Men's Amateur champion Hank Kuehne, she ran off seven birdies in a torrid 10-hole stretch for an 8-under 64. She set a course record and was one off the Open record of 63 posted by Helen Alfredsson in 1994 on a par-71 course.

Kuehne, 22, opened a one-shot lead on tour veteran Juli Inkster (65), runner-up in the '92 Open, and a three-shot margin over Moira Dunn, who never has finished better than a tie for fourth in five years on the LPGA Tour. Defending Open champion Se Ri Pak of Korea, Sherri Steinhauer and Dottie Pepper were at 68 and Karrie Webb, a four-time winner on tour this year, opened with a 70.

"It all worked," said Kuehne, who struggled in '98, her first full year as a pro, and made the Open field by shooting a 68 in sectional qualifying in Austin. "I drove the ball well, my iron play was very sharp and my putting [she needed only 25] was very true."

Old Waverly seemed nearly defenseless against many in the field of 150. Recent dry weather did not allow the rough to grow higher than about three inches, and thunderstorms Wednesday softened greens. As a result, 39 players posted sub-par scores, compared to 11 in last year's first round at Blackwolf Run in Kohler, Wis. Fifteen players were unable to complete today's round because of darkness. They will finish Friday.

"I kept looking for a U.S. Open course, and I never found one," said Kirk Lucas, a Fairfax teaching pro who caddied today for his wife, Kris Tschetter, on her round of even-par 72.

Chuasiriporn finds herself in a tenuous position, probably having to go several shots under par Friday to make the cut. On a vulnerable, wide-open course with huge, sluggish greens, that certainly seems possible, but hardly the scenario she envisioned in her pro debut.

"You can't give away a lot of shots out there," she said. "The worst you should ever make is bogey, but I came into this tournament knowing I had to learn a lot. I'm just going to try to hang in there. That back nine will get some people. It's a little tougher and it really tests your nerves."

Chuasiriporn played in an affable threesome with her idol, Nancy Lopez -- in with a disappointing 76 with two double bogeys in her quest to win her first Open -- and Tschetter. But Chuasiriporn was severely tested shortly after she made the turn holding a one-shot lead.

At the 520-yard 10th hole, she blocked a 4-wood second shot from the fairway way to the right. The ball hit a cart path and bounced 15 yards out of bounds, stopping inches short of a flower bed not far from the condominium she and her family are renting this week. She re-loaded from her original spot on the fairway, hit her fourth shot into the right rough and three-putted from 20 feet for an 8.

"A little mishap at 10 shook me up a little," she said. "It was just mental, and there's no excuse for that."

At the 408-yard 11th, with a lake guarding the left side from tee to green, Chuasiriporn hit her drive in the left rough. Her second shot, another 4-wood, splashed into the pond, skipped a few feet from shore, but never had a chance to hit dry land. She was able to drop her fourth shot about 50 yards closer from the spot her ball crossed the water, and her wedge landed 35 feet short. Two putts from there gave her a double-bogey 6, and she was 2 over for the day.

She staggered in with three more bogeys in her next five holes. She got a bit back with an 18-foot birdie putt at the 171-yard 17th and parred in for her worst Open round since shooting a third-round 78 at Pumpkin Ridge in Oregon three years ago when she finished as low amateur.

Her playing partners today expressed surprise at Chuasiriporn's sudden collapse, as well as admiration for the stoic manner in which she seemed to handle it, rarely changing expression on good or bad shots all day.

"Jenny is a great little player," Lopez said. "I didn't see her emotions change very much from when she was playing very well to when she was struggling, and I respect her for that.

"For some reason, everything seems to change when you have one bad hole, and it's hard to pick yourself back up. But she kept playing and she kept fighting. That's the type of player I like to see play the game, because she just kept trying and never gave up."

Tschetter said: "She hit it absolutely perfect the first nine holes, didn't miss a shot. Her swing is pretty solid. I think she's going to do just fine. What happened to her on the back has happened to everyone out here. It's all part of the learning process."

Kuehne, meanwhile, is learning how to go low. A diabetic who wears an insulin pump while she's playing, she never wilted under the searing sun this afternoon, nor did she seem bothered by a 43-minute delay in play caused by a nearby threat of lightning.

Kuehne had a disappointing rookie season in '98, when she missed the cut in her first six LPGA events. She broke through with her first victory last week at the Corning Classic, a triumph that clearly has had a lovely carry-over effect.

"It was not a fun year," she said of the '98 season. "It was a year of growing pains. It was a difficult transition into professional golf. Last week [winning the Corning Classic] gave me a lot of confidence coming here. I just want to keep it going as long as I can."

CAPTION: After winning Corning Classic, Kelli Kuehne continues to raise her game by taking first-round lead at the U.S. Women's Open. "I just want to keep it going as long as I can," she said.

CAPTION: "It all worked," said Kelli Kuehne, whose round of 64 was one off U.S. Women's Open record.