Dustin Johnson edged closer to golf's world number one ranking Saturday, firing a five-under par 66 to seize a one-stroke lead after two rounds of the weather-hit Genesis Open.
The US Open champion, who could jump from number three in the world to number one with a long sought victory at Riviera Country Club, had a 36-hole total of 10-under par 132.
He was one shot in front of US compatriots Pat Perez, who closed with back-to-back birdies for a 66, and Cameron Tringale, who had seven birdies in an impressive seven-under 64.
It was a further two strokes back to Venezuela's Jhonattan Vegas and Americans Patrick Rodgers and J.T. Poston on 135.
Johnson, whose six top-10 finishes at Riviera include a playoff loss two years ago, could supplant Jason Day atop the world rankings if he can break through for a first win at the classic course west of Los Angeles.
"I want to put myself in position to win this golf tournament, that's really all I care about is what it takes to get it done here," Johnson said. "The rest of the stuff, the points and world golf rankings, yeah, I would like to get there, but I'm not worried about it."
If Johnson wins, Day must finish no worse than a two-way tie for third to hold on to the top spot.
The Australian was eight off the pace after completing his rain-disrupted second round early Saturday.
Day was among the players forced off the course when wind and heavy rain swept through on Friday -- when Johnson never made it to the first tee.
Day said the disruptions were less of a problem than his own "scratchy" game.
"I didn't hit it good," he said. "When you're thinking too much technique you're losing focus of actually the target -- I'm getting in my own way, really."
The third round began shortly after the second ended, but darkness fell before the leaders teed off, and Sunday was shaping up as a marathon.
A confident Johnson was undaunted by the prospect.
"Thirty-six holes can be a really good thing sometimes if you're playing really well, which I feel like the golf game, I'm in control of it right now," he said. "So playing 36 in one day is not going to be a problem."
- Good touch on greens -
Johnson had five birdies, rolling in putts of more than 30 feet at the fourth and 15th, and draining a 20-footer at the 18th.
"I definitely rolled the putter good," he said. "I'm feeling really comfortable over it. I'm seeing the lines really well and I feel like I've got a pretty good touch on the greens right now."
Eighteen players were within five strokes of Johnson's lead. That included two-time major winner Jordan Spieth, who headlined a group on five-under 137.
Those missing the cut at even par included Japan's world number five Hideki Matsuyama -- who also had a chance to overtake Day with a victory this week. He imploded in the adverse conditions on Friday and couldn't get back on track as he closed out a nine-over par second round on Saturday.