ADELAIDE, Australia (AP) -- Playing for the fourth consecutive week, Katherine Kirk wasn't showing any signs of fatigue after shooting an 8-under 65 at Royal Adelaide to take a two-stroke lead after the first round of the Women's Australian Open on Thursday.
The Australian player birdied four of the first five holes on the front nine and three of four in the middle of the back nine at Royal Adelaide.
"There are low numbers to be had out there," Kirk said after her morning round. "A lot of birdie opportunities, and I was just fortunate I got off to a good start and kept the momentum going."
Tied for second with 67s were Marissa Steen and Jane Park of the United States, South Korean Chella Choi and Min Lee of Taiwan, who was the only afternoon golfer to make any inroads on the leaderboard.
Canada's Brooke Henderson was four strokes behind after carding 69. Michelle Wie, using a new putting grip and stance over the ball on the green, shot 70 and No. 1-ranked Lydia Ko had a 71.
No. 2-ranked Ariya Jutanugarn of Thailand, the LPGA's player of the year and a five-time winner in 2016, shot 72 and defending champion Haru Nomura of Japan had a 75, both in tougher afternoon conditions when the wind increased and the greens firmed up.
"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."
Ko was frustrated on the greens, but ended the day on a good note when she birdied the ninth, her last.
"I hit my drives good, which is really important around a course like this, but just the putts did not drop," Ko said. "It was good to see a putt drop on the final hole and hopefully that will give me good momentum going into tomorrow."
Five-time champion Karrie Webb had a 76. She was 3-over after bogeying the first hole - her 10th - but then went double-bogey, bogey, birdie, birdie, par to complete her round.
"A couple of late birdies at least made lunch taste better, but it wasn't real good out there today," said Webb.
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.”