SAMMAMISH, Wash. -- Canadian teenager Brooke Henderson rode a hole-in-one and birdies on three of her final four holes to a 4-under 67, and she holds a two-shot lead after the first round of the KPMG Women's PGA Championship at Sahalee Country Club.
Henderson, 18, aced the 152-yard 13th hole with a 7-iron, which was her fourth hole of the day after beginning on No. 10. She also chipped in on No. 18 to make the turn in 3-under 32.
Henderson, No. 4 in the Rolex Rankings, fell back to 1 under with a pair of bogeys before reeling off birdies on Nos. 6, 8 and 9.
"It was a pretty good day today," Henderson said. "I was trying to get under par, but it's tough to say how hard this course is going to play going into today and for the rest of the weekend."
American Christina Kim and South Korea's I.K. Kim also played in the morning wave and were the only other players to post rounds in the 60s, with both sitting at 2-under 69. Thailand's Ariya Jutanugarn, who has won her past three tournaments, birdied two of her final holes to finish in a large group of players at 1 under.
The marquee group of the morning wave featured top-ranked Lydia Ko from Australia and the top-two ranked Americans, Lexi Thompson and Stacy Lewis. Also starting on the 10th hole, Ko had a pair of birdies to go with two bogeys in an even round of 71.
"There's still so many things to focus on and think about here than think what could happen at the end of Sunday," Ko said. "There's still a lot of golf to be played.
"A lot of the girls are playing good golf. It's not like I'm the only one in the field. I've just got to enjoy it. We know it's tough. So we've got to stay patient."
The third-ranked Thompson had a much more adventurous round, bogeying four of her first five holes and dropping as far as 5 over before birdies on the sixth and eighth holes on her back nine. However, she closed with a bogey on the par-3 ninth hole when she could not get up-and-down from the back of the green.
Lewis was 2 under through 10 holes, but she bogeyed three of her final five holes to finish at 2 over.
"It's always good to play with them," Lewis said of the other stars. "We were talking we haven't played all together for a while. It was good to play with them and see some good golf. The scores don't show it, but everybody played pretty good."
Second-ranked Inbee Park, who qualified for the LPGA Hall of Fame by completing the first round, is five shots off the lead. She was two back of Henderson before her injured left thumb started to get tired on the back nine, with Park bogeying three of her final seven holes en route to a 1-over 72.
Park played with Jutanugarn and American Paula Creamer, who carded a 4-over 75.
Henderson needed just 23 putts Thursday, including nine one-putts.
"Making the turn, I was a little shaky," said Henderson, whose lone previous career title on the LPGA Tour also came in the Pacific Northwest -- an eight-shot victory at the Cambia Portland Classic in 2015. "I hit a couple of bad drives. But I was able to ... scramble, get up and down a couple of times, saved my round. And then I finished really strong on eight and nine."
Henderson won a 2016 Kia K900 for the ace and said she would donate the car to her older sister, Brittany, who caddied for her Thursday. The two posed with the car after the round, with Brittany in the driver's seat.
"All year this year I have walked up on the practice rounds and said, 'See that car, if I get it, it's yours.' I didn't say it this week, but she ends up getting it."
NOTES: South Korean Ji Young Oh received a late spot into the tournament when France's Joanna Klatten withdrew Thursday morning with a "general injury." Playing in the first group off the 10th tee in the morning, Oh carded a 9-over round of 80. ... Gerina Piller, the No. 3 ranked American in the field and No. 16 in the Rolex Rankings, shot a 1-over 72. ... Three-time KPMG Women's PGA Champion Se Ri Pak withdrew after beginning play on the seventh hole, complaining of an arm injury. She was 7-over at the time. ... The course was set up at a par-71 playing 6,624 yards Thursday. ... Former University of Washington player and "Big Break" contestant Sadena Parks shot a 3-over 74.