South Korea's Jiyai Shin held her nerve to claim a comfortable victory in the Wegmans LPGA in Rochester, New York.
Heading into the final round four shots clear, Shin failed to break 70 for the first time this week but a one-under effort left her on a 17-under-par total of 271.
Kristy McPherson and Yani Tseng both hit last-day 66s to claim joint second on 10-under.
However, Morgan Pressel, who started the round as Shin's nearest challenger, crumbled and tumbled down the field with a 78.
Lindsey Wright finished in a share of 15th place following a closing four-over 76 while Karrie Webb was tied for 24th at four-under overall.
Meanwhile, Diana Luna was a comfortable winner of the AIB Irish Open in Portmarnock.
The Italian, who took a one-shot lead into the final round, won with an 11-under-par score of 205, putting her four strokes clear of a trio of players.
The 26-year-old from Rome had a bogey-free final round of four-under-par 68, enabling her to finish clear of France's Gwladys Nocera (69), England's Florentyna Parker and Sweden's Sophie Gustafson (71).
Parker finished with a round of 70, a double bogey on the 15th denying the 20-year-old Germany-born Briton a chance to put pressure on Luna in the closing holes.
Gustafson, a three-time winner of this event, slipped out of contention after double bogeys on the fourth and sixth.
Scotland's Krystle Caithness finished fifth, a further shot back on six-under, with England's Melissa Reid one behind her.
Australia's Frances Bondad claimed a share of 10th place at two-under while Nikki Garrett, Joanne Mills and Dana Lacey were in a large group tied for 36th at five-over.
The event finished late because of two delays for fog. The final round was suspended for 30 minutes from 9.50am due to a dense sea fog which rolled in from across the Irish Sea - and there was a second suspension of more than three hours at 1pm.