Norway's Suzann Pettersen didn't let a hectic morning slow her down, firing a four-under 68 to seize the US Women's Open lead as Michelle Wie surged up the leaderboard behind her.
"My game is very solid," said Pettersen, ranked sixth in the world. "My ball striking is good. My short game is good. And my putting has been really good so far."
Those good things saw her build a 36-hole total of five-under par 139, one stroke ahead of Wie and Cristie Kerr.
Pettersen's round included five birdies and just one bogey as she maintained her focus despite oversleeping and rushing to make her tee time.
"For me breakfast is kind of my most important meal," Pettersen said. "I didn't really have time. I thought it was more important to get stretched and loosened up.
"It's fine. Sometimes that's a good thing. You don't have time to think about stuff."
Pettersen, playing in the group behind Wie, was able to see some of the American's hard-charging six-under 66.
"She was fist-pumping, every putt she looked at," Pettersen said of Wie, who has endured a disappointing season so far.
Wie has missed six of eight cuts this season, but said her game has been coming around.
"The last couple of weeks it started to feel good," Wie said. "Things were coming. My scores weren't showing up as well. But it's a work in progress. Still a long way to go."
Wie, 22, has been making headlines in golf for a decade, qualifying for an LPGA tour event at the age of 12 in 2002.
She competed in a handful of men's tournaments but has battled to find consistent success since turning her attention to the LPGA.
"The fact that you're in contention to have a chance to win the US Open is a big deal," Wie said. "I'm so grateful I have that chance right now. I'm really looking forward to seeing the crowds tomorrow and experiencing it all again."
Pettersen said Wie has plenty of time to mature into a star.
"I think you should give her a break," Pettersen said. "She just graduated, four years in college. That's pretty impressive to do that on the sideline of trying to compete out here."
Kerr, the 2007 US Women's Open champion, shared the overnight lead with fellow Americans Lizette Salas and Brittany Lincicome and followed up with a 71.
"I always draw on that experience, of course, but it's hard to predict what's an advantage and what's not an advantage," Kerr said of her 2007 triumph. "You just don't know."
Salas, 22, fell back with a 73 while Lincicome ballooned to an 80.
"I did nothing right today," Lincicome said. "I couldn't drive the ball. I couldn't do anything right. I couldn't putt."
Germany's Sandra Gal, South Korean Inbee Park and Vicky Hurst were tied on three-under 141, each shooting 70.
World number one Yani Tseng of Taiwan was at two-over after a 72, while defending champion So Yeon Ryu of South Korea carded a 71 to line one-over through 36.