American Cristie Kerr fired a final round of 69 to claim a one-shot victory at the Lorena Ochoa Invitational in Wisconsin, while Australia's Katherine Hull shared eighth place.
Kerr made six birdies and three bogeys during her three-under par round on Sunday, but had to hold her nerve in the final hour of play to take the prize.
The 35-year-old made par on the final three holes to hold off fellow American Angela Stanford and Korean Inbee Park for her 15th career LPGA title.
Park started the final day two strokes in front of Kerr, but dropped shots at the fifth and sixth holes to relinquish her advantage.
The duo then made birdies at the seventh and eighth, before Kerr picked up another shot at the ninth to take the lead on her own.
Stanford eagled the par five 10th to put herself into contention, but could only make one birdie on the way home as Kerr held on.
Fourth prize was shared by American Stacy Lewis and Taiwan's Candie Kung some four shots behind Kerr, while Korean duo Haeji Kang and So Yeon Ryu finished in equal sixth place another shot back.
Lewis' final round of 68 was good enough for her to claim the LPGA Player of the Year honour ahead of Park.
Hull had a mixed day on the greens during her final round, picking up six birdies and making three bogeys to sign for a 69.
It was good enough to share eighth at 10 under alongside Korean Hee Kyung Seo.