Sam Burns birdied the last three holes to seize a two-stroke lead over fellow American Max Homa and England's Matthew Fitzpatrick and after Thursday's opening round of the PGA Genesis Invitational.
Burns, a 24-year-old chasing his first tour victory, fired a seven-under-par 64 at Riviera Country Club for his third top-four start in his past four starts.
"I think just being patient out here (is key)," Burns said. "This golf course at times doesn't offer you a lot of opportunities, so I think just with that mindset going in we were just going to kind of take what we could get."
Fitzpatrick matched his best US PGA first round with a 66 to equal Homa in second with a pack on 67 including Sweden's Alex Noren, Australian Matt Jones, Chile's Joaquin Niemann and American Patrick Cantlay.
"Really pleased," Fitzpatrick said. "To get off to a start like that in the first round, I'm delighted."
Burns eagled the par-5 first hole on a 19-foot putt and birdied the fifth then answered a bogey at the par-3 sixth by dropping his approach inches from the cup for a tap-in birdie at the par-4 seventh. He closed the front nine with a 16-foot birdie putt.
World number 147 Burns took a bogey at 12 after finding a greenside bunker but birdied 13 and then reeled off his fantastic finish -- a birdie putt from just inside 20 feet at the par-3 16th, another frpom 10 feet at the par-5 17th and a final birdie at 18 after leaving his approach within four feet of the hole.
'Hot start'
"Off to a hot start there with eagle on the first hole," Burns said. "We were just pretty consistent throughout the round. We knew we were going to have a tough stretch there to kind of start the back nine."
Fitzpatrick shined despite only reaching 8-of-18 greens in regulation.
"It was a good day overall," he said. "I felt like I played probably better than my tee-to-green stats would suggest. My swing actually felt pretty good. There's a couple loose ones in there, but on the whole it's a great start, couldn't ask for any better."
Fitzpatrick, who began off the 10th tee, birdied the 11th and answered a bogey at 13 by sinking a 43-foot birdie putt at the par-3 14th and rolling in a 10-footer for birdie at the par-3 16th.
He reached the green in two at the par-5 first and rolled in a 25-foot eagle putt and added a three-foot birdie putt at the seventh for his 66.
"It was massive," 20th-ranked Fitzpatrick said of his eagle.
"To get off to a start like that was great. Feel really comfortable with where it's at. It's nice to see all the hard work pay off. Hope it continues."
World number eight Cantlay, also a back-nine starter, birdied four of his last eight holes.
"Four-under on the second nine today was really good," he said. "My game is in a good place and hopefully I can keep it going the next three days."
World number one Dustin Johnson, the reigning Masters champion, opened on 68 with defending champion Adam Scott of Australia shooting 69 and second-ranked Spaniard Jon Rahm on 70.
Four-time major winner Rory McIlroy opened on 73.
South Korea's Kim Tae-hoon, who opened on 69 playing on a sponsor's exemption, made a hole-in-one at the 168-yard par-3 16th hole with a 7-iron. It was a second eagle in his first seven holes that won the world number 291 a new car.