The Bethesda Country Club's foreboding 16th hole promised to be a leading cause of frustrated hair pulling, exasperated club throwing and downright bewilderment at this LPGA Championship. Such drama, however, was supposed to be reserved for a climactic Sunday stretch run.

The 16th, with its minuscule green and debilitating quartet of bunkers, instead claimed its first front-running victim yesterday. Rosie Jones came to the uphill, 192-yard par-3 threatening to run away with this tournament, with a sizzling round in progress that had moved her from a second-place logjam beginning the day to a five-shot lead at 7 under.

She left No. 16 with a wry grin, but it was a smile of resignation rather than joy. A quadruple-bogey 7 moved Jones back toward the pack and made this event a two-round sprint once more, as Sue Ertl completed a second-round 67 after Jones was in the clubhouse to take the lead at 5-under 137 entering today's third round.

"I played an absolutely great round of golf -- besides 16," said Jones, showing little frustration during a sometimes-funny, sometimes-reflective news conference about 45 minutes after she finished play.

"I was laughing and joking on the outside {as she left the hole}, but I was rattled, I was shivering, I was shaking. On the inside, I was scared to death. Thank God I only had two holes to go. That's never happened to me before, and I hope it never happens again because that was hell."

Jones regrouped after the disaster for a pair of pars to stand alone in second at 70 -- 139. Cindy Figg-Currier shot 68 and shares third place with Cathy Johnston at 140. Marta Figueras-Dotti, with 141 after a 69, is the only other player below par.

First-round leader Chris Johnson sank quickly with a 77 that left her in a pack of 10 players at 144. Betsy King, seeking her third major title this year, is eight shots off the lead after a 73, while three-time LPGA champion Nancy Lopez rallied to shoot 70 after a disastrous 78.

Lopez's resurgence put her comfortably under the cut, as the field was pared to 76 players. The required score of 150 is just one below the tour's highest cut of the year, as Bethesda's continued relentlessness left the average round after two days at just over 75.

Colleen Walker, one of four players tied with Jones for second place entering yesterday, suffered a two-stroke penalty en route to a 75 that left her at 144. Walker's playing partner, JoAnne Carner, was disqualified for signing an incorrect scorecard Thursday after she pointed out an error she had made in assessing penalty strokes.

Ertl is a most unlikely leader, given that she never has finished better than fourth in eight years on the tour; she's 68th on the money list with a career-best $41,198, and she conspicuously avoided the word "win" during her post-round analysis.

"If I keep playing like this, I have a great opportunity to lead for two more days," Ertl said. She scrambled a bit yesterday but ended up with a six-birdie, two-bogey outing, including a birdie on the par-3 fourth that she double-bogeyed Thursday. "Just one of those boring 67s," she said with a grin.

She has been remarkable less for her golf than a cult-like following that includes a 100-member fan club in Seattle and "Ertl's Turtles" T-shirts that began during a clinic last year in Richmond. She said she's found her "niche on the tour" and is playing her best golf this year after moving back home to Michigan recently.

"It's great. I'm just really happy these days," Ertl said. "I've found a peace I've never been at before. . . . Everybody has their moment, and this just happens to be mine."

Jones's less pleasant moment came just as she was taking control of the tournament with a style that contradicts nearly every analysis from earlier this week of how Bethesda's trying 6,245 yards would be conquered.

Jones had heard some of her more accomplished comrades on the tour say before the tournament that the course required both power and precision, that Bethesda would expose any minute flaws and guarantee that the game's most prominent names would dominate the leader board.

Jones is on the fringe of that elite group. She's a steady but unspectacular player without a major title among her four championships in eight years as a pro. She hasn't won in two years, suffering through a testing 1989 that included a back injury.

A promising start this year gave way to a brief slump; Jones changed coaches, then switched clubs last week and finished sixth in the Phar-Mor Youngstown (Ohio) Classic. She began this tournament with a 69, missing only two fairways and one green in regulation.

She's not a big hitter, and said accuracy is the prime requisite for success here. Her performance through 15 holes yesterday wasn't as flawless from tee to green as Thursday's outing, but improved putting was allowing her to all but lap the field as longer hitters were being swallowed by Bethesda's unforgiving rough.

"It's a course for straight, accurate hitters," Jones said. "Where are the big hitters? They're stuck in the rough. . . . Unlike the first round, my putter was working {yesterday}. I had a feeling seven-footers would be my friend, and they were."

Two birdies on the front nine, plus a crucial save at No. 8 with an eight-footer for par, left Jones at 4 under. Then she birdied Nos. 10, 12 -- missing eagle by about six inches -- and 14 to move to 7 under and seemingly assure herself of a comfortable advantage heading into the weekend.

She hit what she said was her first bad shot of the tournament at 15, finding rough off the tee, but saved par. There would be no save on the next hole, though, in what is her lone blemish in two days -- she had no bogeys until 16 yesterday. "I still don't have one," she joked.

Her tee shot landed in a bunker to the right of the green, and her attempt to dig out bounced over the green and into the back lip of a rear sand trap. From there she hit too hard and was back in the front bunker, and took two shots to escape.

"I got pretty rattled," she said. "At some point I was just saying, 'Let's just get out of here and get on the green.' . . . The funny thing is, when I {first} went into the bunker, I thought I was going to hit the best shot of the day."

She missed an eight-foot putt for what she said "would have been a good 6," and she was left to ponder what she conceded probably was her first quadruple bogey without the aid of a water hazard. Asked what she'll think about at the 16th tee today, she laughed and said: "I had a 7 here yesterday. I hope I can do better."

Yet she still is in position to win, and said she'll sleep better without the burden of a big lead. "I've had five-shot leads before, and they're no fun," Jones said, recalling how she blew that advantage in eight holes at the 1988 World Championship before recuperating for the victory.

"I'm tickled to be where I am. Now I'm just going to have to work a little harder."