Kathy Baker, a statuesque blond with an elegant swing, shot a two-under par 70 for a three-stroke victory today in a U.S. Women's Open that everyone was waiting for Nancy Lopez to win at Baltusrol Country Club.

Instead, Lopez, who trailed by a stroke going into the final round and was the only player among the five contenders to have won a tournament, bogeyed the first two holes and three of the first four to play herself out of contention. She finished fourth with a birdieless five-over-par 77, even par for the tournament at 288. The Open remains one of the few titles she never has won.

Baker, 24, claimed she was nervous but she never showed it, putting together a round of five birdies and three bogeys to finish at eight-under-par 280, three strokes ahead of Judy Clark, and make her first victory a major. "I don't think it's hit me yet," she said. "I haven't had time to relax and think about it. I was thinking about it a little bit this morning and I had trouble getting anything down, but I tried to put it out of my mind. I'm not sure how it's going to affect me."

Baker earned $40,000 for the victory. Clark shot par to finish five under for the tournament.

The mountainous front nine is the more difficult half of the par-72 Upper Course at Baltusrol and it was fitting that most of the golfers' fates were decided there on the final day. Virtually all of the third-round leaders bowed to Open pressure and the slanting greens of the front nine, which is built on the side of Baltusrol Mountain.

Lopez bogeyed four of the first nine holes. Vicki Alvarez and Janet Coles, both nonwinners on the LPGA Tour who had trailed by two strokes at four under par after Saturday's round, went the same way. Alvarez bogeyed the third, fourth, seventh and eighth holes to finish with a 75, in third place at one-under for the tournament. Coles bogeyed the third, sixth, seventh and ninth to shoot 76, tied with Lopez in fourth place at par.

Baker, a former NCAA champion from the University of Tulsa, pressed on, oblivious to the storied Open nerves that toppled the rest of the field and unbothered by the 90 degree heat and 48 percent humidity. She looked almost cool in a long-sleeved turqoise and blue shirt, stylishly baggy pants and matching earrings as she never lost the one-stroke lead she had held Saturday over Clark and Lopez.

Only Clark, who shot an Open record 65 Saturday, was left to put some fear into Baker. But Baker opened the lead to two strokes on the par-5 eighth hole, with a three-foot putt to go seven under par.

Hitting her irons at the heart of the greens, Baker never gave Clark an opening. She lost her two-stroke lead briefly with bogeys at the 10th and 14th holes, but followed each with a birdie on the next hole. It was suddenly decided on the par-4 16th, where Baker got her fifth birdie and Clark her second bogey. The two-stroke swing gave Baker a four-stroke lead with three holes to play.

"I was four up so I had more security then," Baker said. "I said to myself, 'I don't know how you could possibly blow it now, but just don't.' "

Baker left herself a three-foot putt and stroked it in without batting an eyelash to move to eight under par. Clark's second shot started well, hitting the downslope just in front of the cup, but it rolled back down the hill to the short rough 30 feet away. Her chip fell short as well, and she missed a 12-foot putt.

Lopez's demise was essentially complete when she bogeyed the par-5 first hole. Her chip shot from 30 yards sailed to the back of the green, 12 feet past the hole. Her putt back down the hill rolled four feet past the cup. The next putt ran around the edge. On the par-4 second hole, Lopez stared in disbelief when she three-putted from 30 feet. Her third putt, a three-footer, ran around the hole again.

"I felt humiliated," she said. "When you bogey the first two, you put yourself in a hole real quick. I struggled the rest of the day. You think you're going to play well, then you miss that first putt. The second bogey just made me sick. I was disgusted. I never could get anything started after that."

Lopez continues to be frustrated by the Open. She has won 32 titles in eight years, more than any other professional in that span. But her failure to capture an Open title has invited comparison to Kathy Whitworth, the Hall of Famer who has a record 87 tournament victories, but never won the Open. "I was disappointed," Lopez said. "But I always feel that there are more Opens."

Clark, 35, is an intriguing golfer who is noted for her aggressiveness but curious inability to win tournaments. A seven-year veteran, she was a 13-handicapper at age 28 before she went to former touring pro Gardner Dickinson for help. She is experiencing the best year of her career, with eight top-10 finishes and earnings of $88,306.

"I don't feel snakebit," she said. "I just don't feel I've played the way you have to at the end to win."