PORTLAND, 17 Aug 2015, (AFP) - The 17-year-old Henderson, who only qualified for the tournament on Monday, continued her dream season, capturing her first title by a commanding eight strokes over Thailand's Pornanong Phatlum, Taiwan's Candie Kung and Jang Ha-Na of South Korea.
Henderson closed with a three-under 69 to finish at 21-under 267, breaking the tournament scoring record and joining world number two Lydia Ko of New Zealand and American Lexi Thompson as the youngest players to win an LPGA tournament.
Henderson started the final round with a five-shot lead, widened the gap to nine at the turn and cruised from there.
"It is unbelievable. I am so excited," said Henderson.
Henderson said this experience will give her more confidence in the future.
"My attitude today is a lot better than it was a couple of months ago," she said. "I was just trying to keep going low and push it to get even further under par which I wouldn't have had a couple of months ago."
Pornanong fired a 68 to finish at 13-under 275 along with Jang and Kung, who both shot 70 Sunday at the Columbia Edgewater Country Club.
Spain's Azahara Munoz (69) was tied for fifth along with defending champion Austin Ernst (68) and American Mo Martin (69).
Henderson, who usually plays on a lower level developmental tour, didn't have a caddie at the start of the week.
Her sister Brittany usually caddies for her but couldn't this time because she was also competing this week. So Brooke enlisted the help of family friend Bunk Lee to carry her bag.
The former hockey goaltender is the first Canadian to win an LPGA title since Lorie Kane in 2001.
She also becomes just the second player to win on the LPGA after going through Monday qualifying, joining Laurel Kean, who won the 2000 State Farm Classic.
Henderson has one victory this year on the developmental Symetra Tour and finished in the top five in eight LPGA events, earning her way into those fields through qualifying and sponsor's exemptions. She would need a special waiver to join the LPGA before turning 18, which she will do next month.
Henderson next travels to her homeland for the Canadian Pacific Women's Open that begins Thursday.
"It will be awesome to be back with the Canadian support. That was my first LPGA tournament three years ago so there will be lots of great memories," she said.
Leading scores on Sunday after the final round of the LPGA Portland Classic (USA unless noted, par-72):
267 - Brooke Henderson (CAN) 66-67-65-69
275 - Pornanong Phatlum (THA) 69-69-69-68, Jang Ha-Na (KOR) 68-70-67-70, Candie Kung (TPE) 69-66-70-70
276 - Austin Ernst 72-66-70-68, Mo Martin 67-69-71-69, Azahara Munoz (ESP) 68-70-69-69
277 - Jaye Marie Green 76-68-63-70, Alison Lee 66-71-69-71
278 - Cristie Kerr 67-71-69-71, Alena Sharp (CAN) 67-70-70-71, Morgan Pressel 71-67-65-75
279 - Joanna Klatten (FRA) 72-72-67-68, Sakura Yokomine (JPN) 73-69-72-65, Amy Anderson 65-72-71-71, Kim Soo-Bin (KOR) 69-72-67-71, Ryu So-Yeon (KOR) 68-71-69-71