Haru Nomura dealt with the breezy conditions at Lake Merced to win the Swinging Skirts LPGA Classic by four strokes on Sunday.
Nomura went into the final round with the overnight lead and shot five birdies for a one-over-par 73 as she finished nine under.
South Africa's Lee-Anne Pace (74) finished in second behind Numura, recovering well to hit five birdies after bogeying five of her first holes on the front nine.
Gerina Piller (73) and Choi Na-yeon (75) tied for third at four under, while Ryu So-yeon (75) rounded out the top five at two under.
The win means Nomura ended Lydia Ko's dominance in Daly City after the New Zealander had won the first two editions of the tournament.
World number one Ko (75) was eight strokes behind at one under to tie for sixth with Lexi Thompson (71), Jenny Shin (72), Mi Jung Hur (74) and Brooke Henderson (76).
The victory was just the second of Nomura's LPGA career after the 23-year-old won the ISPS Handa Women's Australian Open back in February.