Canadian Brooke Henderson birdied her last two holes Friday to join Sweden's Caroline Hedwall atop the leaderboard at the LPGA Marathon Classic in Ohio.
"To finish birdie-birdie was really important, and it's fun to see your name at the top," said Henderson, who had five birdies without a bogey in a five-under-par 66.
Hedwall had five birdies and a bogey in her 67 for nine-under par 133.
The pair were one stroke in front of overnight leader Thidapa Suwannapura of Thailand, who carded a second-round 69 at Highland Meadows Golf Club in Sylvania.
Americans Emma Talley and Jacqui Concolino and South Korean Chun In-gee shared fourth on 135.
Henderson is seeking her second title of the year and the seventh of her LPGA career.
"I'm excited to be in the final group," said the 20-year-old from Ontario. "I haven't been in one of those in a couple weeks and it's just a really fun feeling ... hopefully (I'll) just give myself a lot of great looks at birdie and hopefully make them."
Hedwall, 29, is seeking a first LPGA title, to go with eight international victories.
That includes five Ladies European Tour titles earned from 2011 through 2013.
In 2014, Hedwall suffered a wrist injury lifting her luggage off an airport carousel, and her game suffered in recent years as she tried to adapt to playing through the injury.
She holds a share of the overnight lead for the first time in four years.
"I've been in this situation -- it was a long time ago, though," Hedwall said. "This is obviously what you practice and work hard for, to be in contention. I'm just going to try to enjoy myself and play some good golf."
Thidapa struggled Friday to match the 10 birdies she produced in the first round, settling for four birdies and two bogeys in her 69.
"Today, I didn't play my best," said the 25-year-old from Bangkok, who is chasing her first victory on the tour. "I didn't hit it that close to the pin. There were not many birdies today like yesterday. I'm pretty happy I ended up a couple under par today."