Chun In-gee of South Korea edged closer to a second major title, and a slice of golfing history, when she extended her lead to four shots at the Evian Championship in France.
Chun shot a third-round 65 to finish 19-under-par, thanks largely to a strong back nine with three birdies and an eagle.
Her compatriot Park Sung-hyun lies second before Sunday's final day.
China's Shanshan Feng is third at 13-under-par while South Korea's Ryu So-yeon is fourth at 12-under-par.
Victory could also see Chun break the record for the lowest winning score in a major championship by either a male or female.
The record for the women is 19-under-par posted on four occasions, the men's is 20-under-par, set by Jason Day at the 2015 PGA Championship and Henrik Stenson at the 2016 Open Championship.
Chun's third-round total of 194 broke the 54-hole scoring record (199 set by Annika Sorenstam at the 2004 LPGA Championship).
"It is a really big honour for me, but I just have to stick with my game plan," said Chun, who is also looking to emulate Pak Se-ri by winning her first two LPGA titles at major championships.
Chun started the day two shots clear of Park and Feng. Birdies on the second, seventh and eighth gave her a four-shot lead but a mistake on the ninth allowed Park to cut the lead to two shots.
Chun, however, had a strong back nine, including an eagle on the 15th to end the day in a position of strength.
"The pin was on the very top," said Chun. "It was a pretty tough hole. I think I made a really good second shot, and then third shot - because I tried really good to visualise my third shot."
