PLAINFIELD, N.J., JULY 28 -- A record six days, two thunderstorms and an 18-hole playoff after it began, the U.S. Women's Open was finally won today. Laura Davies, who at 23 has established herself as the longest hitter in women's golf, proved she can putt, too, and took the title away to England.

In the tournament's first three-way playoff, Davies played the Plainfield Country Club course in 71 to defeat two accomplished stars, JoAnne Carner and Japan's Ayako Okamoto. Neither of them could even match Plainfield's par, 72.

Occasionally, great sports events actually produce greatness. So with this Open, which seemed to grow in glow as it wore on. First, an epic rain delay pushed Sunday's scheduled fourth round back to Monday, and then 48-year-old Hall of Famer Carner shot a course-record tying 69 Monday to move into the playoff with Davies and Okamoto at 3-under-par 285. She was attempting to become the oldest Open winner.

But today, Davies seized the tournament from the older generation and stamped herself a breathtaking new talent with her round of three birdies and two bogeys. Only the fourth foreign player to win the U.S. title, Davies departed tonight to defend the women's British Open championship she won in 1986.

"I reckon I'm the happiest person in the world," Davies said. "I don't think I know what it means yet. It will take the entire flight home to let it sink in."

It was not a glamorous finish for Carner, who fought an errant driver all day and faded with a round of 2-over-par 74. It was up to Okamoto to produce the drama, which she did with a 73 that would have been threatening had she not lipped out two birdie putts on the final two holes. Had she made those putts of 18 and 12 feet, she could have forced extra holes, for Davies had to save par on 18 with a four-footer.

If that wasn't enough to make this a memorable Open, there was considerable irony and drama in the relationship between Carner and Davies. Davies has said frequently this week that Carner was her childhood hero in Surrey, England. The two have become friends over the course of the tournament, and Davies' long game has frequently been compared to the Hall of Famer's.

"What you have here is an exceptional person, one of those great players who is just now being shown to the world," Carner said.

It was only Davies' fourth tournament on the LPGA Tour, for which she has not yet even earned her playing card. According to LPGA rules, she still has to qualify for the 1988 season despite her victory, although the organization is contemplating a special exemption. In her only other tournament in the United States this season, Davies shot 66 at the Dinah Shore to lead the first round but missed the cut with a second-round 83.

At that tournament, Carner had consoled Davies on the practice range. "Don't worry, it's happened to all of us once," she told Davies. That encounter was running through Davies' mind as she stood over her four-foot par putt on the 18th hole today after Okamoto had missed a birdie. So was a childhood memory of how she used to pretend to be Carner at the U.S. Open as she stood over practice putts.

"I was thinking, 'My God, this is really happening,' " she said.

At 5 feet 10 with a heavily built frame (she says her weight is a secret), Davies belts her drives an average of about 256 yards. The average drive on the men's PGA Tour is 260 yards. Davies also putts nervelessly, has a charming personality and is articulate beyond her years. Further, she has endless patience, which she needed over this 6,284-yard layout.

She sank two birdie putts of 15 feet and another of 30 feet, but Davies was not the sentimental favorite of the 2,000 playoff spectators. That was Carner, whose second and last Open victory came 11 years ago in a playoff with Sandra Palmer.

But Carner had been fighting her driver all week and today it turned on her as she had four bogeys, two birdies, and threatened just briefly. That was at the turn, where her five-foot birdie putt on the ninth hole, combined with Davies' bogey on the 10th, tied them at 1 over par.

That didn't last long, because Carner took bogeys at the 11th and 13th, a pair of par 4s where she drove deep into the rough and could not make saves. A final birdie at the par-4 No. 16 with an 8-iron to four feet was not enough. It was a bittersweet result for the winner of 42 tournaments who let the tournament slip through her fingers Monday when she bogeyed the 18th with a three-putt from the back fringe.

"I had my opportunities and I didn't capitalize," she said. "I had the tournament won Monday and I opened the door for the other two . . . But I can't really be disappointed. I would love to have won, but that's how it goes. It's been fun. Cheers."

For Okamoto it was yet another crushing loss in a major this year. The third-leading money winner on tour, Okamoto has been painfully close, finishing fifth at the Dinah Shore, tying for third at the LPGA Championship and taking second at the Du Maurier in Canada. In that last one, she led by six strokes going into the final round only to shoot 74 and lose to Jody Rosenthal's 66. She has three tour victories for the season but no majors.

"It does feel better than the Du Maurier," she said through an interpreter. "Losing like that can really depress you. Here it's not like I played badly."

In fact, Okamoto's 73 was a fair round on a course that had defied low scorers all week. She had two bogeys on the front nine to trail most of the day and never seemed in contention as she made nine straight pars on the seventh through 15th holes. But her 18-foot birdie on 16 set up a charge at the end that just missed along with her birdie bids on 17 and 18.

"I couldn't get enough birdie chances," she said. "But I was making good pars and I knew the others might make some bogeys. I thought I had a chance right up until the last hole. I never gave up."

But the knockout blow of the round probably came with Davies' consecutive birdies on 14 and 15. She was aided by her brother Tony, who caddied and read her putts for her all week. On 14, she stood over a 15-footer just briefly before knocking it in to go back to par for a two-stroke lead over Okamoto and three-stroke edge over Carner.

On the 130-yard 15th, all three players had birdie chances. But Carner misread an eight-footer, and Okamoto watched a 12-footer flirt with the hole. Meanwhile, Davies consulted with Tony, who told her the 30-footer she faced would break a full two feet. It did, and Carner and Okamoto could scarcely believe it as it fell in.

"It must be the putt of my life," Davies said. "It was the critical hole for me," Carner said. The putt was "marvelous," said Okamoto.

Her day, said Davies, was "fun."