Yuka Saso carded a four-under-par 67 to earn a one-stroke lead at the halfway stage of the U.S. Women's Open.
Saso – who has modelled her swing on four-time major champion and former men's world number one Rory McIlroy – used a strong second round to soar to the top of the leaderboard on Friday.
The 19-year-old Filipino – making her third appearance at the LPGA Tour major event – had six birdies to go with two bogeys at the Olympic Club.
After birdieing her final hole, Saso is now six under through 36 holes heading into the weekend in San Francisco, where 2019 champion Lee Jeong-eun is her nearest rival (67).
Megan Khang (70) and amateur Megha Ganne (71) – the overnight leader alongside Mel Reid – are two shots off the pace, while Shanshan Feng is a stroke further back following her 70.
Inbee Park – a two-time winner of the U.S. Women's Open – recorded a two-under-par 69 to be tied for sixth alongside Lexi Thompson (71) and Reid (73).
Defending champion Kim A-lim missed the cut at seven over following a second-round 70, having opened with a 79.