Rory McIlroy overcame a stuttering start to roar into the mix with two eagles in three holes in the Genesis Invitational at Riviera.
The Holywood star (30), had to dig deep for his first seven holes as he followed a three-putt bogey at his third hole with some brilliant scrambling before flexing his muscles to card a three-under 68.
After curling home a 12 footer for par at the 16th, his seventh, he rifled a 290-yard three-wood to the heart of the 596-yard 17th and rolled in a 35-foot eagle putt to move into the red.
A bogey at the 18th was only a minor blip as he bounced back immediately with another eagle from just five feet at the first.
"It was good after the start," said McIlroy, who birdied the tricky fifth and ended his day four shots behind Matt Kuchar, who fired a seven-under 64 to lead by three shots in the clubhouse from Russell Henley and South Korea's Kyoung-Hoon Lee.
"One-over through seven, missed a couple of short ones early on and went through a stretch of missing a lot of greens.
"But I got it up and down on 13, 14 and 15 and the eagle on 17 kick-started things a little bit."
Admitted his par save at the 16th was key, he added: "There are no easy putts on this golf course and that was nice.
"I feel that part of my game helps me stay in rounds and putt like that give you a little bit of momentum going to the next tee.
"You hit a couple of good shots and get a bonus by holing a long one and all of a sudden you are one-under par and things are looking okay again."
He matched young gun Patrick Cantlay and outscored Dustin Johnson by four shots as world number two Brooks Koepka, who could return to number one with two-way tie for seventh, eased to a 69.
Meanwhile, Royal Dublin's Niall Kearney carded a two-under 71 on the Links at Fancourt to lead the Irish challenge in the Challenge Tour's Dimension Data Pro-Am.
South Africa's Christiaan Bezuidenhout shot an 11-under 61 on the Outeniqua Course to lead by a shot from Spain's Santiago Tarrio as Robin Dawson shot 73 at the Links and Gavin Moynihan a two-over 74 on the Montagu Course.