SYLVANIA, Ohio (AP) ― Alison Walshe put herself in prime position at the Marathon Classic for her first LPGA Tour victory.

But as the name of the tournament implies, the race has just begun.

Walshe shot a 6-under 65, her best score in her four years on the LPGA Tour, to take a one-stroke lead Thursday in the opening round of the tournament formerly known as the Jamie Farr Toledo Classic.

Also daunting is the ‘Who’s Who’ of stars on her heels. Paula Creamer, who won the tournament five years ago, and top-ranked Inbee Park, winner of the year’s first three major championships, were within two shots.

Walshe, among the top 20 on tour in putting stats, three-putted at the first hole for bogey ― then took only 19 putts on the next 17 holes.

“I was like, ‘Here we go again,’” Walshe said. “Then I one-putted the next hole and got my confidence going.”

She also chipped in for birdie on the 14th hole, her fifth of the day, to jump-start her round.

Walshe came into the Marathon, in its first year under its new title sponsor, quietly. She hasn’t had a top 10 placing this year and ranks 55th on the money list with earnings of slightly more than $120,000.

Everybody in the 144-player field had to deal with the high temperatures, high humidity, little wind and a glaring sun. Teenager Lexi Thompson, who was tied with Canada’s Jessica Shepley and Creamer at 66, said after her round that she drank a bottle of water per hole to stay hydrated.

Creamer, who opened with a career-low 60 in her 2008 victory at the course, was satisfied to be a shot off the pace.

“I had a lot of shots out there that I could have gone lower with,” she said. “But at the same time, it was a good start. I haven’t been able to start off the way I wanted the last couple of events, so this was nice to post a good number.”

Thompson, who was the youngest winner ever of an LPGA event when she took the 2011 Navistar at the age of 16, was asked if American players had been eclipsed by the South Koreans who have dominated in recent years.

“There are a lot of good American golfers out here. There is so much competition,” she said. “It doesn’t matter where you’re from; it matters how well you bring it out on the golf course.”

No one questions how well Park has played. She’ll go for an unprecedented fourth consecutive women’s major in the same year when she heads for the Women’s British Open later this month.

She’s already won six times on the tour this year while ascending to No. 1. Naturally, galleries expect her to win every time out.

“I do feel more pressure coming into this tournament,” she said after a 67 that left her tied with Haeji Kang, Jacqui Concolino, Gerina Piller and Karine Icher. “But I try to enjoy it. I enjoy the fans coming out to watch.”

Defending champ So Yeon Ryu had a 68 along with a large group that included Morgan Pressel and Natalie Gulbis. Se Ri Pak, a five-time winner of the tournament, opened with a 69 ― the same as the world’s top-ranked amateur, Lydia Ko.