Defending champion Lexi Thompson fired a 9- under 63 on Thursday to grab a 2-shot lead after the opening round of the Navistar LPGA Classic.
Thompson, who cruised to a 5-stroke win on The Senator Course last year, carded a career-low round that matched the tournament's 18-hole scoring record.
"My record was 65 here before, so I'm pretty excited about this golf course," said Thompson, who shot 65 as a 14-year-old in 2009. "But the whole day, I was just really consistent. I think I hit 17 greens and dropped a good amount of putts, but it gave me a lot of confidence."
Hee Young Park and Lizette Salas, who were in the final two groups of the morning wave, both shot 7-under 65 and are tied for second.
World No. 3 Stacy Lewis posted a 6-under 66 and was joined in fourth place by Karen Stupples, Mi Hyang Lee, Wendy Ward and Amanda Blumenherst.
Thompson was on fire right from the start. She got going with a birdie on the first. She converted a birdie effort on the par-4 fourth and followed with birdies at five and six to quickly get to minus-4.
The 17-year-old picked up one final birdie on her front side as she birdied the ninth. Thompson made it two in a row at 10.
Thompson had an outside shot at shooting 59 after being 6-under after 10 holes, but she parred four of her next five holes.
In the midst of those pars, she birdied the par-3 13th. Thompson also birdied the par-3 16th and followed with another birdie on the par-5 17th. She parred the last to lead by two.
"I'm really comfortable out here. I hit a lot of drivers and take pretty aggressive lines," Thompson stated. "It definitely rewards good shots out here and that's what I like. Build up your confidence and just try to make birdies."
Salas was the first of the two in second place to shoot 65. She flew out of the gate with three birdies in the first four holes, but then stumbled to bogeys at five and six.
After a par on seven, Salas ran off four birdies in a 5-hole span from the eighth to jump to 5-under. She birdied 14 and 15 to move to minus-7, then parred the last three holes.
"The whole goal this week is to stay in the fairway and just stay out of trouble and hit fairways and greens all day," Salas explained. "And my wedge game was really good today and I rolled in the putts that I needed to, and I occasionally dropped in a couple of long ones and I got up and down when I needed to."
Park spread her seven birdies out. She birdied the first, fourth, sixth and eighth to make the turn at minus-4. Park birdied 11, 14 and 17 to grab a share of second place.
NOTES: Stacy Prammanasudh first set the course record of 63 in 2007 and that number was matched six other times prior to today ... Salas is one of four rookies in the top 10 on the leaderboard ... Lee is 153rd on the money list and has the most work to do among those near the top of the leaderboard to keep her tour card for 2013.