California - Roberto Castro, Jason Kokrak, and PGA Tour rookie James Hahn all shot nine-under par 63s on Thursday to share a one-stroke lead after the first round of the $5.6 million Humana Challenge.
Rookie Russell Henley, coming off a three-stroke win in the Sony Open on Sunday, was among the quartet of players lying one stroke back on eight-under 64. He was tied with Australians Greg Chalmers and Aaron Baddeley and Dough LaBelle.
Phil Mickelson launched his 2013 season with an inconsistent round of even-par 72 that left him nine off the pace.
VIDEO: Humana Challenge Round 1 highlights
Mickelson, recovering from flu-like symptoms, had three birdies, one bogey and a double-bogey at La Quinta Country Club, one of three courses used in the tournament in which the opening rounds are played in a pro-am format.
Kokrak had two eagles and five birdies at La Quinta. Castro had nine birdies at PGA West's Jack Nicklaus Private Course and Hahn had nine birdies on PGA West's Arnold Palmer Private Course.
"The course over at La Quinta is in great shape," Kokrak said. "Greens are not overly fast, so you can be somewhat aggressive out there. The greens are holding. So you can be aggressive with the iron shots out there."
Castro capped his round with a birdie putt of more than 40 feet. He was pleased he was able to take advantage of the good scoring conditions offered in the balmy California desert.
"This tournament you kind of got to get it going and keep it going," he said.
Hahn's round included two chip-ins for birdies, something he said hadn't happened for him since he was nine years old. He said not knowing the course was actually an advantage.
"I think a lot of the times, we as professionals, try to take in too much information," he said. "Some of my best rounds have come from not even seeing a golf course for the first time. It gives me tunnel vision ... I just know fairway, green and try to make a putt."
Henley posted his 64 on the Nicklaus course.
"I'm feeling very confident," Henley said. "I definitely wasn't going to be upset either way ... The last thing I want to do is waste any energy and be emotional right now. I think I've got to conserve all my emotions and my energy as much as I can so I can play another full golf tournament."
Leading first-round scores on
Thursday in the $5.6 million US PGA Tour Humana Challenge on the Palmer
Course, Nicklaus Course and La Quinta Country Club course (USA unless
noted, all courses par-72):
63 - Roberto Castro, Jason Kokrak, James Hahn
64 - Russell Henley, Greg Chalmers (AUS), Doug LaBelle, Aaron Baddeley (AUS)
- Jeff Maggert, Daniel Summerhays, Michael Bradley, Ricky Barnes,
Charley Hoffman, Cameron Tringale, Ryan Palmer, Jerry Kelly, Patrick
66 - Johnson Wagner, Stewart Cink, Zach Johnson, Darron
Stiles, Kevin Stadler, Jimmy Walker, Robert Garrigus, Bo Van Pelt, Scott
Stallings, Bryce Molder, Richard H. Lee, Bobby Gates