Australian Minjee Lee fired eight birdies in an eight-under par 64 on Friday to grab a share of the lead alongside Cheyenne Knight in the LPGA Mizuho Americas Open at Liberty National in Jersey City, New Jersey.
Lee roared out of the gate with birdies at the first three holes, and was six-under at the turn after birdies at the fifth, eighth and ninth.
The world number five added birdies at the 10th and 12th for a 36-hole total of seven-under par 137.
Knight joined her with a four-under par 68. The American teed off on 10 and was even par through her first nine after two birdies and two bogeys.
She, too, birdied the first through third holes, and capped her round with her sixth birdie of the day at the ninth.
The leading duo had a one-shot lead over world number three Lydia Ko of New Zealand, who carded a 69 for 138.
World number one Ko Jin-young of South Korea waited out a late weather delay to post a six-under par 66 and head a group on 139 that also included sixth-ranked Atthaya Thitikul of Thailand, No. 8 Brooke Henderson of Canada, India's Aditi Ashok and Rose Zhang -- the 20-year-old American making her pro debut after dominating the amateur ranks for the past two years.
The weather was no trouble for early starter Lee, who turned things around after a one-over 73 on Thursday.
"I didn't really feel like my score reflected how I played yesterday, so I just came in with a positive attitude," she said.
"I knew there was probably going to be less wind this morning, so just tried to take advantage of the good conditions that were given to me."
She hit 10 of 14 fairways and 14 of 18 greens, needing 24 putts in her impressive second round.
"I holed some really great putts today," Lee said after her best round since the 2022 Founders Cup -- when she shot a nine-under 63 in the second round on the way to a victory.
"A few long ones and a few mid-range -- I don't think I had any tap-ins, so they were all really great putts," she said.
Knight said her birdie burst to start her back nine was crucial.
"That really got things going and kind of kept the momentum up for me," the American said.
New Zealand's Ko had an early bogey at the third, but responded with back-to-back birdies at the sixth and seventh and another brace at the ninth and 10th.
"I think I played really consistently," Ko said. "I haven't been playing that great leading up to this week. I played much better and solid on the (Ladies European Tour) event a couple weeks ago, so that was a good momentum shift."
Ko Jin-young was delighted to finish her strong round, after dangerous weather caused play to be suspended late in the day when she had just a few holes to play.
"I played really well today," she said. "I think I'm so lucky to finish, I'm going to go get great sleep and then I'm looking forward to the weekend."