Los Angeles - Justin Thomas eagled the first hole of the third round on Saturday to open a one-shot lead over Adam Scott at the rain-hit Genesis Open, where Tiger Woods was surging as darkness halted play.
Thomas and Australia's Scott shared the 36-hole lead on 11-under par after both completed six-under par 65s in the rain-delayed second round.
Thomas, who had 14 birdies in the 30 holes he played on Friday, kept the momentum going over six second-round holes on Saturday morning with a birdie at the fifth and a par at the par-three sixth - where he used a wedge on the green to chip over the distinctive bunker in the middle of the putting surface.
Hours later he rolled in a 13-foot eagle putt at Riviera Country Club's par-five first hole to move to 13-under par, separating himself from Scott who birdied the same hole before both parred the second.
Americans Patrick Rodgers and J.B. Holmes were both 11-under par with 16 holes to play.
"It just is such a long day," Thomas said. "It's good to get off to a good start and go home and get some rest."
The third round was set to resume at 6:45 am (1445 GMT), as organizers pushed to complete a tournament that lost seven hours to a rain delay on Thursday.
"It's not going to be light yet," said Woods, noting that players warming up for a 7 am start on Saturday could barely see.
Thomas, facing the prospect of playing 33-plus holes on Sunday, noted that the forecast also called for more rain and brisk winds.
"I'm going to need to be patient because I'm playing so many holes," he said, "stay in it emotionally and stay patient, see what we can do."
Scott, too, was bracing for a lot of golf on Sunday, but said that also offered an opportunity.
"It's a big day, a lot of golf," Scott said. "It's a great day to get your rhythm early and make a move ... hopefully by the middle of the final round you've taken a whole bunch of guys out of the equation."
Tournament host Woods, who made the cut with one stroke to spare, wasn't ready to be counted out.
He was five-under through his first four holes to vault into a tie for 14th at six-under par.
"Made a couple of putts," said Woods, whose struggles this week on the greens included four three-putts in the first round.
He rolled in a five-foot birdie putt at the 10th, followed that up with a 10-footer for eagle at 11, a 21-foot birdie at 12 and a 10-footer at 13.
"I putted well," Woods said. "Hit a lot of good shots."
But Woods was short of the green with his third shot from the rough at the par-five 17th when he departed the course, facing a tough up and down when play resumes.
"I've got some work to do," Woods said. I've got to get up and down at 17. Number 18's not going to be playing short with these temperatures.
"It's going to be a tough day for all of us and one that we're going to have to fight through."
Leading second-round scores on Saturday in the rain-disrupted US PGA Tour Genesis Open (third round underway. USA unless noted. Par-71):
131 - Justin Thomas 66-65, Adam Scott (AUS) 66-65
132 - J.B. Holmes 63-69
133 - Patrick Rodgers 66-67, Michael Thompson 69-64
134 - Tony Finau 66-68, Jordan Spieth 64-70
135 - Rory McIlroy (NIR) 72-63, Kyle Jones 68-67
136 - Vaughn Taylor 67-69, Bubba Watson 70-66, Paul Casey (ENG) 70-66
137 - Luke List 71-66, Beau Hossler 68-69, Jon Rahm (ESP) 67-70, Kelly Kraft 69-68, J.T. Poston 67-70, Joaquin Niemann (CHI) 71-66