Venezuela's Jhonattan Vegas surged into a share of the lead with Boo Weekley after the second round of the Bope Hope Classic.
PGA Tour rookie Vegas, who learnt to play the game using a broomstick and a rock, fired a five-under 67 on the Nicklaus Private course at PGA West, one of four venues being used this week.
That left him on 13-under-par overall alongside former United States Ryder Cup star Weekley, who birdied his last two holes for a 66 on the Nicklaus layout.
"I'm just hitting it great from the tee which is always good, especially on a course like this," said Vegas. "It was a great round."
Asked how he felt to be at the top of the leaderboard in a PGA Tour event, he replied: "It's a lot of fun. I'm enjoying it as much as I can because we know how complicated golf can be.
"I'm having a good time, as I always do. I'm just loving it, trying to play the best I can. So far, things worked out."
Vegas, who reached the semi-finals of the 2007 US amateur championship, has come a long way since first picking up the game from his father in Venezuela.
"I hit plastic balls, rocks, whatever I could find and start hitting everything around the house, breaking windows and all kinds of stuff," he said.
"That's kind of how my game started, just by looking at my dad. He's always been a big fan of golf and so just by looking at him I started doing it."
Weekley was delighted to enjoy another productive day on the greens after struggling with his putting at the end of last year.
He has switched to a new 34-inch putter and, so far, the move has reaped instant reward.
"I feel comfortable with this putter," Weekley said after totalling 27 putts on the day.
"From three to 15 foot, I feel like I can make it. I was hoping that this would happen."
American duo Chris Couch (65) and Charles Howell III (66) sit a stroke back at 12-under-par, with Englishman Brian Davis (66) and Keegan Bradley (67) a further shot behind.
Among the bigger names competing in the third PGA Tour event of the season, former world number one David Duval is at nine under after carding a 67 at La Quinta Country Club and a stroke in front of last year's money list winner Matt Kuchar (70).