Japan's Nasa Hataoka fired a four-under-par 67 and emerged with the third-round lead at the LPGA LA Open on Saturday after top-ranked Ko Jin-young stumbled down the stretch.
The two were tied for the lead through 15 holes at Wilshire Country Club. Hataoka birdied 16 as playing partner Ko bogeyed and any chance Ko had of applying pressure over the last two holes evaporated with a disastrous quadruple-bogey eight at the par-four 17th.
She dropped five shots in the space of two holes before a closing birdie saw her sign for a one-over-par 72 that left her tied for third with compatriots Park In-bee and Kang Hae-ji, five shots off the lead.
Australia's Hannah Green was in second, four shots behind Hataoka.
Hataoka, seeking a sixth LPGA title, said "something clicked" in her game on Friday and that carried through to Saturday as she posted five birdies and a bogey.
"Compared to yesterday, today wasn't really bad," Hataoka said of the tricky breezes on the California course. "(I) feel like the wind yesterday was a lot more difficult to read."
In the end, that didn't help Ko much after what she called a "big mistake" at 17.
When her second shot landed in a steep-sided barranca, she twice tried unsuccessfully to hit out before taking an unplayable lie.
"This is golf, I don't have regret," Ko said.
Green, who also played in the final group, had three birdies and a bogey in her 69.
"I feel like I haven't played my entire best," the Aussie said. "I'm hoping tomorrow I can kind of get everything to go my way and try and put as much pressure on Nasa as possible."
LEADING THIRD ROUND SCORES
202 - Nasa Hataoka (JPN) 67-68-67
206 - Hannah Green (AUS) 70-67-69
207 - Park In-bee (KOR) 72-67-68, Kang Hae-ji (KOR) 69-69-69, Ko Jin-young (KOR) 71-64-72
209 - Lilia Vu 74-69-66, Chella Choi (KOR) 71-71-67, Minjee Lee (AUS) 70-68-71
210 - Yealimi Noh 73-71-66, Amanda Doherty 70-70-70, Celine Boutier (FRA) 69-71-70, Kim Sei-young (KOR) 68-72-70, Liu Yu (CHN) 71-68-71
211 - Ji Eun-hee (KOR) 73-70-68, Allisen Corpuz 72-71-68, Angel Yin 74-68-69, Marina Alex 71-71-69, Sanna Nuutinen (FIN) 71-70-70, Pauline Roussin-Bouchard (FRA) 69-72-70, Madelene Sagstrom (SWE) 69-72-70, Jenny Coleman 73-67-71, Lizette Salas 69-70-72