Kiwi Lydia Ko shot a 5-under 67 to be three strokes off leader Celine Boutier at the Founders Cup in Phoenix.
Ko finished the first round in a tie for 12th along with Brooke Henderson who also shot 67.
Na Yeon Choi feared the worst in her return from a back injury. She ended up high on the leaderboard after shooting a 7-under 65 at Desert Ridge in her first tournament round in 11 months.
"Golf is really funny game. I didn't expect any good score today because this is first day," said Choi, the 2012 US Women's Open champion and nine-time tour winner. "I practice hard, of course, but it's hard to tell how I'm going to shoot. Less expectation, I think, always give you better result."
Close friend Jenny Shin waited for Choi to finish and threw a cup of Champagne on her in celebration.