LOS ANGELES, 17 Apr 2016, (AFP) - The 19-year-old from Perth closed with a bogey free eight-under par 64, just 24 hours after shooting a two-over 74 at the Lotte Championship.
"I had a not-so-great round yesterday," Lee said. "I just came out with a fresh mindset."
She finished at 16-under 272 to beat South Korea's Chun In-Gee and American Katie Burnett by one stroke at the Kapolei, Hawaii golf course. Burnett was the lone American golfer in the top six.
Thailand's Moriya Jutanugarn, 21, finished in sole possession of fourth at 14-under after firing a 68 on Saturday.
Jan Su-Yeon of South Korea rounded out the top five at 13 under after posting a final-round 71.
Lee chipped in for eagle on the par-five 13th hole and had six birdies during a seven-hole run that launched her up the leaderboard.
She rolled in a birdie putt on the par-four 17th hole and saved par with an up and down from off the green at No. 18 to claim her second North American win to go with a victory at the 2015 Kingsmill Championship.
"I eagled the 13th hole and that was kind of the turning point," Lee said. I made that eagle then followed it with two birdies."
Lee became the fifth player to win twice before her 20th birthday, joining Lydia Ko, Lexi Thompson, Marlene Hagge and Sandra Haynie.
She also finished in the top 10 (tied for ninth) at last year's Women's British Open.
The red-hot Chun could have finished in a tie at the top but missed a 20-foot birdie putt on No. 18.
"It had a chance to go in but it was a very tricky green," Chun said.
The defending US Women's Open champion Chun had six birdies en route to a 67 as she finished runner-up in just her second start after a freak collision with a suitcase that sidelined her for a month.
Chun was riding the escalator at Singapore's Changi Airport when she was struck by the hard cased suitcase that got away from the father of fellow South Korean Jang Ha-Na. She sat out with an injured back but tied for second two weeks ago in her return.
The 26-year-old Burnett was unable to hold on to the lead and finished with a 70. Her undoing was a three-putt bogey on the par-three 16th hole and missed birdie putts on 17 and 18.
Ko, the top-ranked women's player in the world, closed with a 69 to tie for 23rd at five-under, her worst finish this year.
Leading final-round scores on Saturday in the Lotte Championship in Ko Olina, Hawaii (USA unless noted, par-72):
272 - Min-Jee Lee (AUS) 68-66-74-64
273 - Chun In-Gee (KOR) 74-67-65-67, Katie Burnett 70-66-67-70
274 - Moriya Jutanugarn (THA) 68-70-68-68
275 - Jang Su-Yeon (KOR) 71-66-67-71
276 - Joanna Klatten (FRA) 71-70-67-68
277 - Megan Khang 76-64-70-67, Mo Martin 72-71-66-68, Kim Sei-Young (KOR) 69-69-69-70
278 - Nontaya Srisawang (THA) 70-71-71-66, Feng Shan-shan (CHN) 73-68-69-68, Brooke M. Henderson (CAN) 69-70-71-68, Pernilla Lindberg (SWE) 70-72-67-69, Lexi Thompson 75-66-68-69