Starting her round with three successive birdies, Lee carded two more on the 8th and 12th holes on her way to a five-under-par 67.

She ended the day tied for sixth, two shots shy of outright leader Ruixin Liu of China, who was still suffering from allergies that forced her to withdraw from last week's Portland Classic.

It didn't stop her from posting a sevenunder 65 on Thursday for her best round of the year and a one-shot lead over Peiyun Chien, Elizabeth Szokol, Dottie Ardina and Linnea Strom.

Liu started strong – including five birdies on her outward nine – her lone regret came on the 12th hole when she hit her approach to 18 feet but three-putted for a par.

She had seven birdies through 13 holes and closed with five pars.

"I pretty much made everything except for hole No.12," Liu said.

"That's the only bad hole I played today, because my second shot was only like 18 feet for eagle and I three-putted."

Following her severe allergic reaction in Portland, Liu said she still didn't have a clear head for the opening round in Cincinnati and was surprised to play so well.

"I'm very happy to take it," she said.

China's Ruixin Liu holds the first round lead in Ohio. PHOTO: Getty Images.

The Queen City Championship is the final LPGA event before the Solheim Cup on September 22 to 24 in Spain, and some of the better performances came from European players.

Emily Kristine Pedersen of Denmark and England's Charley Hull, a runner-up in two majors this year, finished alongside Lee on 67.

Lydia Ko and Women's PGA champion Ruoning Yin were at 68.

Australia's Gabi Ruffels offset her six birdies with three bogeys to finish the day at three-under-par alongside Madelene Sagstrom of Sweden and Americans Jennifer Kupcho and Ally Ewing, the defending champion at Kenwood.

Lexi Thompson showed little improvement. Thompson is having her worst year on the LPGA Tour but still made the Solheim Cup team through the women's world ranking.

Thompson, who has missed five of her last six cuts, made double bogey on the last hole for a 73.

The LPGA Tour is coming off a week that delivered one of the biggest surprises of the year after Thai teenager Chanettee Wannasaen, a Monday qualifier who was World No.367, won the Portland Classic.

Liu might be another surprise. She is a six-time winner on the Futures Tour but has never finished in the top-10 on the LPGA Tour in individual play.

She is World No.250 and her best result is a tie for 20th.

"I don't want to give myself too much expectation because physically I don't feel great," Liu said.

"I'm just going to take a good break, try to sleep good, and try to do the same thing tomorrow."