Jiyai Shin broke the women's course record at Hoylake on Saturday, a blistering eight-under 64 pushing the South Korean five strokes clear of the field after the weather-delayed British Open second round.
Compatriot Inbee Park (68) was in second place on four-under 140 at the final major championship of the year. Japan's Mika Miyazato (70) and seven-times major winner Karrie Webb of Australia (70) shared third spot on 141.
Shin hit all 18 greens in regulation, never found a bunker and only missed one fairway as she fired six birdies and an eagle.
"I can't believe the way I hit it, 64 shots today on this course which is really tough," she told reporters.
"On the back nine it was blowing a very strong wind but I just stayed focused on my tempo."
Gusts of up to 60mph had caused havoc on Friday. The players found it difficult to keep their golf balls on the green or the tee and play was suspended for the day after only 78 minutes with all scores scrapped.
The final 36 holes will now be played on Sunday.
Shin made a confident start on Saturday by chipping in from 30 yards for an eagle three at the 10th.
She followed up with a hat-trick of birdies before picking up another stroke at the 16th.
Shin made further inroads on par at the fourth and seventh to post her best round in a major.
The lowest scores in a women's major are the 62s recorded by Minea Blomqvist at the 2004 British Open and Lorena Ochoa in the 2006 Kraft Nabisco Championship. (Editing by Justin Palmer)