GALLOWAY, N.J. – Laura Diaz didn't know that she'd be making the first start of her 20th LPGA season until last Saturday, and she put in the preparation time that she hoped would lead to a good showing at the ShopRite LPGA Classic.

She obviously did a great job of getting her game in shape as shown by a 5-under-par 66 in Friday's opening round that put her into a tie for the lead with two-time ShopRite LPGA champion Anna Nordqvist and France's Celine Herbin on the Bay Course at the Stockton Seaview Hotel and Golf Club.

But the other factor that led to the good score was her caddie, her 12-year-old son, Cooper, whom she said helped keep her relaxed.

"I'm very happy with how I played, and it's more special because I have my son with me," said Diaz, 43, of Winston-Salem, N.C. "He wasn't nervous. He was perfect. So it's a calming influence. I think I spent more time worrying about him.

"There was a little bit of nerves in the last few years. They really seemed to get to me more, so I think my biggest challenge is figuring out how to not let them get to me. He's a huge asset in that because I can focus more on him than me."

Scores were low during a breezy first round, with 65 of the 144 contestants bettering par and another 15 matching it. A logjam of eight players, including major championship winners Lydia Ko, Pernilla Lindberg and In-Gee Chun, were together at 67 while a group of 14 at 68 included defending champion I.K. Kim.

Diaz's only two LPGA Tour wins came in 2002 when she finished seventh on the money list with more than $843,000. She made four U.S. Solheim Cup teams, the last in 2007. She has cut back on her schedule in recent years to watch Cooper in baseball, golf and basketball, and her 8-year-old daughter Lilly in swimming and soccer.

When tournament officials released the field on May 30, Diaz was the third alternate but withdrawals allowed her to gain a spot. Her only other competitive event this year came May 15 in an unsuccessful attempt to qualify for the U.S. Women's Open.

On Friday, she did not make a bogey and birdied two of Seaview's three par-5's. Her final birdie of the day came at the short par-3 17th.

Nordqvist won this event in 2015 and 2016, finished second last year and continued her fine play Friday with no bogeys. Playing in the afternoon, when the greens were a little bumpier and the wind a bit stronger, she finished up with a birdie on her last hole, the par-5 ninth.

"I have a lot of good memories from here," said Nordqvist, who will celebrate her 31st birthday on Sunday. "It's a place that makes me happy. I seemed to be striking the ball better today than I have for most of the year. I was very consistent."

Herbin, playing in the next-to-last group of the day that started at No. 10, moved into a share of the lead with birdies on her last two holes. She had made just five of 11 cuts this year prior to this tournament.

Ko, a former world No. 1 player making her first appearance at the Jersey Shore since 2014, also finished with a birdie at No. 9 to get into the 4-under group, as did Chun, winner of the 2015 U.S. Women's Open when it was held at Lancaster Country Club.

Lindberg, the winner of the year's first major, the ANA Inspiration, highlighted her round by holing out a 7-iron from 144 yards out for an eagle at the par-4 13th.