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Sylvania, Ohio (SportsNetwork.com) - Laura Diaz fired an impressive 9-under 62 on Thursday and she holds a 4-shot lead following the first round of the Marathon Classic.

Seeking her first victory on the LPGA Tour since winning twice back in 2002, Diaz was bogey-free and leads Austin Ernst and Lee-Anne Pace by four shots at Highland Meadows Golf Club.

Ernst and Pace, both of whom played in the afternoon groups, already knew they were chasing a low number with Diaz having posted her score in the morning groups. Ernst and Pace finished their rounds at 5-under 66.

Three-time LPGA Tour winner and 17-year-old Lydia Ko is five shots back of the lead at 4-under 67. She is joined there by Ricoh Women's British Open winner Mo Martin, Katie Burnett, Mariajo Uribe, Lindsey Wright and Marissa Steen.

Defending champion Beatriz Recari ended the day eight shots off the lead at 1- under 70, while U.S. Women's Open champion Michelle Wie struggled to a 3-over 74, putting her well off the pace.

It looked as if it was going to be Diaz's day right off the bat as she came out on fire. Starting on the back nine, Diaz drained five straight birdies from No. 10, and just like that she was 5-under through five holes.

"I just kept trying to hit good shots and execute the putts," Diaz said. "I changed my putter this week so I went out really hesitant with my putter and then I made five birdies in a row, so that helped knowing that, hey, the putter is good."

She cooled off a bit with two pars at 15 and 16, but Diaz got right back on the birdie train at 17. She made the turn with a par at 18 and added two more pars at one and two.

Back-to-back birdies at three and four put Diaz at 8-under, but she was not done yet. The 39-year old made three straight pars from No. 5 before making her ninth birdie of the day at No. 8. She ended with a par at No. 9.

"I'm very happy to shoot 62. I would be lying if I said I wasn't," Diaz said. "It's nice to get a good feeling after round one. To see the ball going in the hole, I think that's always a boost. To see it rolling and rolling in and then getting close on the ones that don't go in. So I feel good."

Diaz is not too worried about following up this successful round on Friday and she plans to go out and do what she did on Thursday.

"I don't really think about it. You know, every day you have to follow up a round," Diaz stated. "Every time we tee it up, unless it's Sunday, you're following it up the next day with a round. I'm going to do what I do ever day: practice, putt."

NOTES: In 11 events this year, Diaz has missed the cut five times and has not finished in the top 10. She ended tied for 23rd at the LPGA Classic, which is her best finish of the season ... World No. 1 Stacy Lewis ended round one eight shots back at 1-under 70.