Danielle Kang carded a four-under 68 to win the Tournament of Champions in Orlando by three strokes over Canada's Brooke Henderson.
Kang finished on 16-under while picking up her sixth career LPGA victory.
The 29-year-old resident of Las Vegas fuelled her victory with four birdies in a five-hole stretch on the back nine, and shot below 70 in all four rounds at Lake Nona Golf and Country Club.
"My mental game was really good," Kang said. "I had a really good attitude all day today and yesterday. I know I left some putts out there, but I never let it get to me and I kept having to give myself birdie chances as much as possible."
Henderson posted 70, while Mexico's Gaby Lopez shot even-par 72 to finish third on 12 under, as France's Celine Boutier (71) and world number one Nelly Korda (75) tied for fourth on 10-under.
Kang was one-under through 10 holes before going on her spree.
She posted a birdie on the 11th hole, made par at 12 and then knocked down three straight birdies to move to 17 under. Even a bogey on 16 didn't hurt as Kang finished off the win.
"I feel great about a lot of the work that I've done," said Kang. "I'm so thankful for my team. It takes a village to get here, so still feels a little bit surreal. Just trying to kind of take in the moment and go with the flow and see."
Korda held the third-round lead but had a poor final round, making just one birdie while carding four bogeys.
Her lone birdie on 15 pushed her to 12 under but there would be no late charge as she bogeyed the next two holes.
"I struck it pretty bad all week but my short game saved me, so that was nice," said Korda.
"Overall, you know, I didn't play very good but I'm going to take some positives away from this week."