Inbee Park will take a three-shot lead into the final round of the Lorena Ochoa Invitational.
The world number two fired a third round 67 to move to 10 under, with Sei Young Kim next best on seven under. So Yeon Ryu and Carlota Ciganda are a further shot back on six under.
Park, who needs to finish at worst in a tie for eighth if she is to have a chance of edging Lydia Ko to the year-end honours, had stalled slightly with a 71 on Friday, but she found form once more on Saturday.
The South Korean began strongly with a birdie at the first, but that was her lone deviation from par on the front nine. Park got things rolling on the back nine though, with three birdies in five holes from the 10th to the 14th.
A bogey at the 15th briefly stifled her progress before birdies at the 16th and 17th rounded off a third-round 67.
Speaking after her round, Park pointed to improved level of control as being key to her success.
"I was able to make a lot of putts and I was able to control the shots a bit better today," Park said. "It's a definitely a plus, because the last couple of days I've been making a lot mistakes."
Kim rose up the leaderboard on the back of a 66 on Friday, but three bogeys in five holes on the front nine – after opening with an eagle at the second – saw her progress slowed.
Ryu will be left cursing a late stumble, with the South Korean five under for the day after 14 holes before a double bogey at the 15th meant she had to settle for a 69 and six under overall.
Ciganda too managed a 69, but at one point the Spaniard's round was in doubt after she, along with overnight leader Minjee Lee, Suzann Pettersen and Angela Stanford, missed their tee times when a tournament-provided shuttle took two-and-a-half hours to get to the course.
"It was just crazy. We just couldn't believe it," Ciganda said. "It was too much traffic and we didn't know what was going on."
The players were allowed to begin their rounds at a delayed time.
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