PGA Tour rookie Davis Thompson has shot a career-low 10-under 62 to take a two-stroke lead over Jon Rahm and four others after the first round of the American Express tournament in California.
Australia's Harrison Endycott sits a shot further back on seven under after a bogey-free round featuring seven birdies.
Jason Day is tied for 27th after a first-round 67, Aaron Baddeley finished one under and Cam Davis ended even after day one.
The 23-year-old Thompson got off to a brilliant start with birdies on three of the first four holes and then making eagle on both par-5s on the front nine.
He made the turn in eight-under 28, the lowest front-nine score at La Quinta.
That flawless start on a sunny day in the Southern California desert put Thompson two clear of Rahm, Tyler Duncan, Taylor Montgomery, Matti Schmid and Sam Burns.
"I just got off to a hot start and kind of coasted on my way in," said Thompson, who finished with a birdie.
"It's always good to see some putts go in early and give you confidence to just keep it rolling."
Rahm, the world's fourth-ranked player who won two weeks ago at the Tournament of Champions in Hawaii, shot 64 at La Quinta, one of three courses being used for the first three rounds.
After the cut at 54 holes, the final round will be played at the Stadium Course at PGA West.
"I'll be picky about a lot of things. But it's a great start to the tournament," Rahm said.
"You can't really win it on this golf course, but you can sure fall off the pace.
"It's a great start, solid round of golf, great putting out there."
The field includes five of the top seven players in the world and 10 of the top 20.