Jennifer Rosales came alive with five back-nine birdies to join Lindsay Wright, Caroline Hedwall and Katie Futcher atop a crowded leaderboard in the Mobile Bay LPGA Classic.
The quartet were tied for the lead on five-under par 67, with another eight players right behind them on 68.
The Philippines' Rosales, who won the most recent of her two LPGA Tour titles in 2005, was even through nine before her late surge on the par-72 The Crossings course.
Rosales is playing her first LPGA tournament of the season. After finishing 124th on the money list last year she has limited tour status.
She said she'd enjoyed her off-season activities, including scuba diving, and was trying not to put too much pressure on herself.
"Actually, you know what? It's better not to expect anything," Rosales said. "I just came out here and wanted to play and see this weekend. ... Actually, today was an easy day for me. I hit most of the fairways and greens. I only missed I think a green today. My putting was very good today."
Futcher briefly took sole possession of the lead at six-under through 17 holes, but dropped back into a tie with a bogey at her last hole, the par-fourninth.
Both Australia's Wright and Sweden's Hedwall played without a bogey.
"It feels like it's kind of target golf and I like that," Hedwall said. "I enjoy just hitting it where it stops where you hit it, too. I like that and I think I did that well today."
Wright, who won the New Zealand Women's Open in February, also said her day was uneventful.
"I just played a nice round of golf," she said. "I wish it was like that every day."
The big group on 68 was led by South Korean Sun Young Yoo, winner of the first women's major of the year at the Kraft Nabisco Championship.
"I hit the ball well and putted well," Yoo said. "I missed a couple putts, but four-under is a good score so I'm pretty happy with where I'm at right now."
She was joined by fellow South Korean's Haeji Kang and MJ Hur along with Stacy Lewis, Morgan Pressel, Colombia's Mariajo Uribe, Sydnee Michaels and Cindy LaCrosse.
Another eight players shot 69.