Graeme McDowell fired a 6-under 66 on Friday to jump ahead by three shots at the World Challenge.
This event, hosted by defending champion Tiger Woods, is taking place at Sherwood Country Club outside Los Angeles, California. The field is made up of 18 of the top 35 players in the world rankings.
The 2010 U.S. Open winner McDowell finished 36 holes at 9-under-par 135. He defeated Woods in a playoff at this event in 2010.
"It's nice to come to a golf course which has got some good memories for me and greens that I've always enjoyed putting on," McDowell told the Golf Channel after his round. "I managed to make a few today."
Keegan Bradley, who is at the forefront of the controversy surrounding the USGA and R&A's recent anchoring proposal, used his belly putter to card a 69 for the second consecutive day.
He is tied for second place with Bo Van Pelt (68) and Jim Furyk (69).
Woods, a five-time champion at this event, is alone in fifth place at minus-5. Last year, he collected his first win of any kind since 2009 when he edged Zach Johnson by a single stroke. The drought lasted 749 days, 107 weeks and 27 starts, by far the longest span in between victories for Woods.
"I'm hitting the ball better today than I did yesterday," Woods, who shot 69, said in a post-round TV interview. "My putting and my speed has been good so I'm pleased about that."
Overnight leader Nick Watney stumbled to a 73 to fall into a tie for sixth place with Rickie Fowler (67) at 4-under.
Jason Dufner (68) is 3-under, Dustin Johnson (68) and Matt Kuchar (69) are tied for ninth at 2-under, and Brandt Snedeker (68) and Webb Simpson (73), another notable name affected by the anchoring ban, are 1-under.
McDowell, who entered the day two shots off Watney's pace, opened with three straight birdies to jump into contention. He dropped a shot on the par-4 seventh, then recorded a pair of pars before unfurling a sparkling outward nine.
The run started with a birdie on No. 10 and another on the 13th, but Van Pelt applied pressure with a strong run of his own -- he didn't drop a shot over his first 15 holes and picked up five birdies over that span to pull even atop the leaderboard.
McDowell responded with consecutive birdies starting at No. 16, which led to a 3-stroke advantage when Van Pelt was forced to settle for a bogey on the par-4 last.
Zach Johnson (70), Steve Stricker (71) and Hunter Mahan (73) are tied for 13th at even par, European Ryder Cup hero Ian Poulter (72) and Bubba Watson (74) are 1-over and Jason Day (75) is alone in last place at plus-2.
NOTES: This is the 14th year of the World Challenge ... Dufner and Snedeker are competing in this event for the first time ... Eleven of the 12 players from the American Ryder Cup team are in the field -- only Phil Mickelson is not playing this week ... Woods won the tournament in 2001, 04, 06-07, 11. He also owns four runner-up finishes.