Moriya Jutanugarn and Amanda Blumenherst carded matching 5-under 66s on Friday to share the lead at the ShopRite Classic.
The duo is trailed by defending champion Stacy Lewis, who is a stroke off the pace following her 67 on the Bay Course of the Stockton Seaview Hotel and Golf Club.
Michelle Wie sits in fourth place at 3-under, while Shanshan Feng, Beatriz Recari, Hee Young Park, Ji Young Oh, Pornanong Phatlum, Jennifer Song and Sara-Maude Juneau are tied for fifth at minus-2.
Chella Choi had a share of first place with five birdies over her first seven holes, but tripped to bogeys at the second, fourth, seventh and ninth during her inward nine to fall four strokes off the pace and into a group of players tied for 12th at 1-under.
Jutanugarn was the first of the co-leaders to hit the course and opened her round with back-to-back birdies at the first and second before tripping to her lone bogey of the day at the third.
After parring her next eight holes, the 18-year-old moved to 2-under with a birdie at the 12th.
She then closed with a flurry, picking up three shots over her final four holes to take the clubhouse lead.
"My game today, I hit the tee shots like in the -- I hit it in the fairway a lot, so it kept me in the places that are easy to play. But the greens were kind of getting firmer and firmer, and it's more -- you have to see like -- it's in good shape, but you have to see like where you can miss it and where you cannot," Jutanugarn said.
Blumenherst was not far behind, however, as the American quickly got into red numbers with an eagle at the third before trading a bogey at the sixth with a birdie at the ninth to make the turn at 2-under.
She pulled within a shot of Jutanugarn with consecutive birdies at the 12th and 13th, and then moved into a share of the lead by picking up another shot at the 17th.
Blumenherst closed with a par to stay there.
"It's been a while since I've had a very solid round of golf and felt like I just played well throughout the entire day," said Blumenherst. "It was a lot of fun. It was a lot of fun out there because it's been a challenging start to the season."
Lewis started on the back nine and made the turn at 2-under following a pair of birdies at the 13th and 15th.
She picked up a couple of more shots at the third and fifth before tripping to a bogey at the sixth.
After parring the next two holes, the two-time winner this season closed with a birdie at the ninth to move into second place.
NOTES: Se Ri Pak, who won this event in 1999, withdrew prior to the first round due to illness ... Song-Hee Kim withdrew during her first round, while Marina Stuetz withdrew after completing her first round due to severe allergies. Stuetz recorded a 10-over 81 ... Candie Kung withdrew after completing her first round with an 8-over 79.