World No.2 spot for Minjee Lee with LA win April 29, 2019 by AAP

LOS ANGELES, AP - Australian Minjee Lee will reach a career-high ranking of world No.2 after she claimed her first LPGA Tour title of the season and fifth of her career.

The 22-year-old sealed a four-shot victory at the LA Open with a 15-foot birdie putt on the par-3 18th to close with a three-under 68 and finish at 14-under 270.

Lee was projected to jump from fourth to second in the world rankings when they are released on Monday after her fourth top-three finish in her past seven starts, and second in as many weeks.

"Coming in, the first half of the year that I've had, I've been hitting it pretty solid and playing pretty solid," Lee said.

"I felt like it was close. I feel pretty good with this one."

Lee earned $225,000 ($A412,000) for her victory, taking her to second on this season's LPGA money list and the Tour's season-long points Race to the CME Globe.

"For the rest of the year I will do my best, have fun and try and get a couple of more wins," he said.

Only three Australians have more career LPGA wins - Karrie Webb (41), Jan Stephenson (16) and Rachel Hetherington (eight).

Lee's previous win was in May 2018 at the Volvik Championship and she has two runner-up finishes this season.

Lee took a one-shot lead over Nanna Koerstz Madsen into the final round at Wilshire Country Club but it was Sei Young Kim that made a charge to finish second.

The South Korean closed to within two shots of Lee on the back nine on Sunday but bogeyed the 18th for a 66.

"This golf course is not easy, even regular tournament," Kim said.

Lee comfortably maintained her advantage despite a bogey on the par-4 11th.

"I was just going to carry on playing my own game," she said.

"I had a couple birdie opportunities coming in, so I didn't get rattled up or anything."

Annie Park (67) and Morgan Pressel (68) tied for third at nine under.

Koerstz Madsen shot a 76 to finish 13th at five under. She was trying to become the first Danish winner of an LPGA event.

Lee's countrywoman Hannah Green, who shared the lead after round one, carded an even-par 71 in the final round to finish in a tie for 14th and four under.