Katherine Kirk set the early pace at the Women's Australian Open on Thursday, shooting an 8-under 65 at Royal Adelaide to take a two-stroke clubhouse lead.
The Australian birdied four of her first five holes and three of four in the middle of the back nine. Tied for second were Marissa Steen and Jane Park of the United States and South Korean Chella Choi.
Canada's Brooke Henderson was four strokes behind after carding 69, while No. 1-ranked Lydia Ko shot 71. Five-time champion Karrie Webb shot 76 ahead of the afternoon starters.
"Four birdies, no bogeys, I'm pretty happy and hopefully will shoot another similar round tomorrow," said Henderson, who played with Ko.
"The crowds were awesome. I hardly ever see that many people on the Thursday round, especially when we tee off (early) in the morning."
Webb had an up-and-down second nine after starting on the 10th. She was 3-over after bogeying the first — her 10th hole — but then went double-bogey, bogey, birdie, birdie, par to complete her round.
Steen was in the first group out, and took advantage of it during her round which included an eagle on the third.
"The wind was low, the greens were rolling really pure. I was joking that I didn't see a blade of grass out of place out there the whole day," Steen said. "I didn't trip once. I either hit every green or was right on the fringe where I was still able to putt, so I gave myself a lot of chances and took advantage when I had wedges in my hands."
Steen, 27, didn't start playing golf until she was 14.
"I played a bunch of other sports growing up, so focusing on golf I was a little late to it," said Steen, who played at the University of Memphis in Tennessee for four years and then played Symetra Tour for three seasons.