SAMMAMISH, Wash. (AP) Brooke Henderson beat top-ranked Lydia Ko with a birdie on the first hole of a playoff Sunday in the KPMG Women's PGA Championship after overcoming a three-shot deficit on the back nine.
The 18-year-old Canadian, ranked No. 4 in the world, closed with a bogey-free 6-under 65 - the best round of the week at Sahalee - to match Ko at 6-under 278. Ko finished with a 67.
In the playoff on the par-4 18th, Henderson hit her second shot from 155 yards to 3 feet, while Ko's second from farther back in the fairway left her with 20 feet. Ko missed to the left, and Henderson tapped in to cap a week that started with a hole-in-one on her fourth hole of the tournament and ended with a major championship.
In regulation, Henderson saved par on 18 with a 12-footer, moments before Ko missed a 4-foot birdie try on the par-3 17th. Henderson also made a long eagle putt on the par-5 11th and birdied the par-3 13th. She won last year in Portland, Oregon, for her first tour title.
Henderson became the second-youngest winner in a major championship, with Ko the youngest last year in the Evian Championship in France. Henderson also ended the 19-year-old Ko's bid for her third straight major victory.
Ariya Jutanugarn, in search of a fourth straight victory, shot a 66 to finish a stroke back. The 20-year Thai player missed a birdie putt on the 18th that could have put her into the playoff.
Henderson, the first-round leader after a 67, began the day at even par - two strokes behind Ko - after consecutive rounds of 73. The Canadian pulled off the comeback with a perfect back nine after going out in 2 under. Henderson's eagle at the 11th was just the third at the long par 5 all week and separated her from a large pack at 2 under. Ko answered with a birdie at the 11th, but Henderson drew another huge roar with a birdie at the 13th to stay one shot behind.
Both continued to make pars until the 17th when Henderson dropped a 50-foot birdie putt after pulling her tee shot to the wrong side of the green on the par 3. And Henderson managed to make par on the 18th the first time despite pushing her tee shot in the trees down the right side.
The 17th also made the difference for Ko. After hitting a perfect tee shot, Ko left her short birdie putt out to the right and missed the chance to take a one-shot lead to the final hole. Ko missed a lengthy birdie putt the first time playing the 18th.
''I'm happy with the way I played. I just got outplayed,'' Ko said. ''For Brooke to shoot 65 on the final day at a major, at a course like this is very impressive.''