Chinese teen Yin Ruoning fired a six-under par 65 to match South Korean Choi Hye-jin and Spain's Carlota Ciganda for the lead after Thursday's first round of the LPGA Dana Open.
World number 421 Yin, a 19-year-old rookie, birdied six of the last 10 holes to grab a share of the lead after 18 holes in the 37th edition of the LPGA stop at Highland Meadows Golf Club in Sylvania, Ohio.
"For the last month I spent my time on short game and putting and I think that paid off a little bit," Yin said.
Yin, coming off a wrist injury, missed the cut in seven of her nine prior LPGA starts this year but delivered her best tour round by three strokes to join the leaders.
"I just want to play my best out there," Yin said. "I just want to enjoy it."
Making only her 12h LPGA start, Yin began with a birdie and answered her lone bogey at eight with three birdies in a row starting at the ninth.
Yin birdied the par-3 14th and par-4 16th before a closing birdie at the par-5 18th.
"The bogey was kind of motivation for me," Yin said. "I set a goal before the round -- just don't be afraid -- and I was so mad after that I tried to make some birdies."
Choi birdied three of the first four holes and added another at the par-3 eighth. She began the back nine with a birdie and sank another at 13 then parred her way to the clubhouse in a bogey-free round.
World number 18 Choi, also a rookie chasing her first LPGA victory, was third at this year's US Women's Open and shared fifth at the Women's PGA Championship.
Choi shared second at last week's Canadian Open, her ninth top-10 showing of the season.
Ciganda also birdied 18 to finish on 65, the 32-year-old from Pamplona firing a bogey-free round.
"I started very solid," Ciganda said. "Then I just told myself to keep giving chances, hit greens. It's key on this golf course.
"I feel very comfortable out there. I really enjoy playing here and it has been a great day."
World number 40 Ciganda, who won her sixth Ladies European Tour title in July at Barcelona, won her only two LPGA titles in 2016 at South Korea and Mexico.
Her best finish of the season, a share of third at the Evian Championship, also matched her best career major showing.
Ciganda made back-to-back birdies at the par-3 second and par-4 third holes, sinking birdie putts of 15 and 10 feet respectively.
She opened the back nine with back-to-back birdies, sinking a 30-foot birdie putt at 10 before landing her approach inches from the hole at 11, and added another at 13 before grabbing the lead with her closing birdie effort, a 5-wood to the green and two-putt birdie.
"Very happy with the round, and especially no bogeys," Ciganda said.
Sharing fourth on 66 were Ireland's Leona Maguire, New Zealand's Lydia Ko, Denmark's Emily Pedersen, Germany's Aline Krauter, South Korean Kim Hyo-joo and Americans Lexi Thompson, Amy Olson and Lauren Stephenson.
Defending champion Nasa Hataoka of Japan opened on 69.