Park Sung-hyun opened up a two-stroke lead over the rest of the field after the first round of the Evian Championship.
Having finished joint-second at this event last year, the South Korean placed herself in an excellent position to go one better this time around thanks to an eight-under 63 in Evians-les-Bains.
Park is chasing her second major title of 2017 following her success at the U.S. Open in July, while her momentum from that triumph was maintained with another LPGA Tour win at the Canadian Pacific Women's Open three weeks ago.
After inclement weather on Thursday forced tournament organisers to reduce the event to 54 holes, Park sits two shots clear of Moriya Jutanugarn, who birdied the 18th to move into second outright.
Anna Nordqvist and Katherine Kirk sit one shot further back on five under.
Park began Friday's round at the 10th and was quickly into her stride with a birdie, followed by another at 12 and an eagle three at 13.
She picked up further shots at 15 and 17 before her progress was checked slightly by her only bogey at the par-four fourth.
The South Korean was undeterred, however, securing birdies at seven and nine to take up a position of strength as she looks to follow in the footsteps of compatriots Chun In-gee (2016) and Kim Hyo-joo (2014) in winning this event.