The previous world No 1 posted a one-under 71 at Lake Merced Golf Club to join Minjee Lee at the highest point of the leaderboard on 12 under, before terminating a staggering methodology on the principal sudden-passing gap and changing over a short proximity hawk putt for triumph.
Charley Hull completed three strokes baczk on eight under, with a two-under 70 seeing her offer third spot close by Shanshan Feng, Angel Yin and Jessica Korda.
Ko took a one-shot lead in to Sunday yet came up short three of her opening six gaps to open the entryway for the pursuing pack, just to come in a 10-footer at the seventh and include another birdie at the tenth.
The New Zealander bobbed again from an intruder at the eleventh by contributing from off the thirteenth green and influencing a two-putt to increase two openings later, as Lee coordinated the birdie at the fifteenth and holed out from a dugout at the seventeenth to recover an offer of the preferred standpoint.
Lee – playing in the gathering ahead – birdied the last to set the clubhouse focus at 12 under, just for Ko to nearly gap her falcon chip on her way to a tap-in pick up on the standard five to broaden the challenge.
The two players came back to the standard five eighteenth and Lee missed the green in two, as Ko nearly holed her second shot to leave a two-foot putt for a first triumph since July 2016 read more story.