Jang Su-Yeon, who needed a sponsor invite to get into the event, fired a bogey-free 65 to grab a three-shot lead heading into the final round of the weather-plagued Lotte Championship on Friday.
South Korea's Jang reached a total of 17-under 199 and is aiming to become the first sponsor's invite to win on the US LPGA Tour since New Zealand's Lydia Ko captured the Canadian Women's Open four years ago.
Canada's Alena Sharp (66) and Cristie Kerr (62) of the US are tied for second at 14-under 202 in the tournament which has featured weather delays in each of the first three rounds.
Chun In-Gee of South Korea fired a seven-under 65 for fourth place and Thailand star Ariya Jutanugarn is also still in the hunt after shooting a 70 take sole possession of fifth. Ryu So-Yeon is alone in sixth after a 69.
Weather forecasters are predicting more rain for Saturday's final round but Jang's not worried.
"I had a great feeling for my shots and putting today," she said.
"Because I had to finish up the second round this morning and playing another 18 I was a little bit tired, but I know I'm so far away from home and I travelled so long to play this tournament, so I try to tell myself just to suck if up and have a good time and play a good round today."
Sharp is seeking her first career USLPGA Tour victory. She had a chance at having second place all to herself but made bogey on the final hole.
"I didn’t even know what I was shooting really. I was just kind of on autopilot," said Sharp. "I was very happy with how I played.”
World number one Ko fired a seven-under-par 65 on Friday with no bogeys, and is seven shots adrift of Jang.