PORTLAND, 15 Aug 2015, (AFP) - Henderson, who turns 18 next month, is not yet a member of the LPGA Tour but showed a veteran's poise in a bogey-free round that saw her finish on 18-under 198.
"I had a lot of fun out there today," said Henderson. "I got some lucky breaks out there. I think that's due to my positive energy. I try to focus on my shots and block out any negativity.
"Overall it was a great day and I'm really looking forward to tomorrow. I feel like I'm in a really good place."
The former hockey goaltender, who only booked her spot in this week's field as a Monday qualifier, is only playing her ninth LPGA event of the year, but two of those were shares of fifth place in majors -- at the Women's PGA Championship and US Women's Open.
Henderson was a contender at the LPGA North Texas shootout as well as a 36-hole tournament record-setter in April at the LPGA Swinging Skirts Classic in San Francisco, where she finished third.
"In San Francisco and Texas I had similar experiences being close to the lead," said Henderson. "I gained from that physically and emotionally."
Henderson opened with back-to-back birdies, added another at the par-5 seventh and had back-to-back birdies again to open the back nine and on 15 and the par-3 16th.
American Morgan Pressel also fired a 65 to stand second on 203, one stroke ahead of Germans Sandra Gal and Caroline Masson and two ahead of Taiwan's Candie Kung and South Korean Jang Ha-Na.
Pressel was ready to make a run at Henderson after her second round in a row with nine birdies.
"You don't make nine birdies if you can't get it in the hole," Pressel said. "Anything within 10 feet, I was good. I just need to hit a few more balls closer to the hole."
Pressel changed her putting fortune when she squared up her stance for round two.
"I feel very comfortable the last couple days of getting the ball on the right line and seeing the speed," Pressel said.
After four birdies and two bogeys on the front side, Pressel birdied the par-5 10th and 12th and then birdied three of the last four holes.
Leading scores on Saturday after the third round of the LPGA Portland Classic (USA unless noted, par-72):
198 - Brooke Henderson (CAN) 66-67-65
203 - Morgan Pressel 71-67-65
204 - Sandra Gal (GER) 67-72-65, Caroline Masson (GER) 70-64-70
205 - Jang Ha-Na (KOR) 68-70-67, Candie Kung (TPE) 69-66-70
206 - Alison Lee 66-71-69, Jenny Shin (KOR) 67-68-71
207 - Jaye Marie Green 76-68-63, Min Lee (TPE) 72-67-68, Cristie Kerr 67-71-69, Azahara Munoz (ESP) 68-70-69, Pornanong Phatlum (THA) 69-69-69, Alena Sharp (CAN) 67-70-70, Mo Martin 67-69-71, Julieta Granada (PAR) 66-69-72
208 - Kim Soo-Bin (KOR) 69-72-67, Ryu So-Yeon (KOR) 68-71-69, Austin Ernst 72-66-70, Lisa Ferrero 71-67-70, Amy Anderson 65-72-71
209 - Maria McBride (SWE) 70-71-68, Lizette Salas 70-71-68, Yoo Sun-Young (KOR) 72-69-68, Lee Mi-Rim (KOR) 71-68-70, P.K. Kongkraphan (THA) 71-68-70, Lin Xi Yu (CHN) 69-68-72, Sydnee Michaels 69-68-72, Kim Kaufman 69-67-73