South Korea's Sang-moon Bae birdied nine holes en route to a six-under 65 that left him tied with Sweden's Fredrik Jacobson in the second round of the Northern Trust Open.
Bae, a 26-year-old in his second full season on the US PGA Tour, got off to a blazing start at sunsplashed Riviera Country Club, opening with four straight birdies from the 10th as he positioned himself for a run at a first PGA Tour title.
Bae's nine-under par total of 133 stood up as the lead for much of the day, but Jacobson briefly overtook him with his seventh birdie of the day at the 13th before dropping back with his only bogey of the day at 15 and also finishing with a 65 for 133.
They were one stroke in front of Americans John Merrick and John Rollins. Merrick carded a 66 and Rollins posted a 65 highlighted by an eagle at the 11th for eight-under 134.
World number three Luke Donald carded a 66 for 135, one stroke better than former Masters champion Charl Schwartzel of South Africa (67), reigning US Open champion Webb Simpson (66) and England's Lee Westwood (68).
Bae took a conservative approach at the classic par-71 Riviera course in the Pacific Palisades west of downtown Los Angeles.
"Keep it on the fairway and hit the greens," he said of a strategy that rewarded him with birdies at half of his holes.
"I feel like I played very well today," Bae said. "I hit a bunch of good shots. I made many good putts."
Bae also missed a couple of short ones -- that included a two-footer that failed to drop at the fifth hole, where he made one of his three bogeys.
"It was not a big problem. These greens are a little tricky and soft and bumpy," Bae said. "Actually my putter is feeling at my best level -- I can make a 10- or 15-foot putt. I have confidence in my game."
Jacobson, sidelined late last year with a back injury, came in with some confidence after finishing with a share of seventh up the coast at Pebble Beach last week.
The most unlikely of his seven birdies came at the par-four ninth, where he rolled in a 54-foot putt from about five feet off the green to launch a burst of three birdies in a row.
"That putt was pretty spectacular," Jacobson said. "I was just short left of the green and there was a lot of slopes and bumps along the way there to get it there but managed to trickle over the edge."
Jacobson said he was pleased that his back was holding up well to both competition and practice, but said he hadn't changed his expectations after his top-10 finish at Pebble Beach.
"I haven't really played any rounds with any expectations other than I'm going to go out and do my absolute best," he said. "I don't really have any numbers in mind or anything like that. I just go out and try my hardest and try to work as hard as I can."
Donald, making his first competitive start of 2013, was pleased with his game.
His cause was aided by three birdie putts from the fringe, a 41-footer at the par-four 15th, a 22-footer at the par-four third and a 71-footer at the par-three fourth.
"Obviously coming off a pretty good break you never know how you're going to deal with being back in competition again, but certainly a big improvement today ball-striking wise and my short game has been very sharp," he said.