World number one Justin Rose shot a six-under-par 66 to open up a three-stroke halfway lead at the Farmers Insurance Open in San Diego on Friday.
While Tiger Woods posted his second consecutive 70 to slip 11 strokes off the pace, Rose excelled on the Torrey Pines south course in southern California to sit at the top of the leaderboard on 15-under 129, matching the best 36-hole score for a PGA Tour event at the venue.
Japan's Hideki Matsuyama showed signs of life after a recent period in the doldrums, matching Rose's 66 on the south to jump into second place on 12-under.
Matsuyama was ranked world number two less than 18 months ago but has slipped to 33rd.
Spanish overnight leader Jon Rahm battled to a 72 on the south to slip five strokes behind Rose, equal third with Americans Billy Horschel (68) and Ryan Palmer (67).
Rose found fairway bunkers with poor drives at the first two holes but salvaged par both times before hitting his stride with three straight birdies from the fourth.
"Job was done today," he told Golf Channel. "It was nice to play a positive round and feel good so I can build on that hopefully going into the weekend.
"If you play well the course is there to be had but what I like about it is you need to be on. If you don't drive it well, or hit some poor iron shots, you can't fake it around here."
Northern Irishman Rory McIlroy shot the day's lowest score, a 65 on the easier north course, to move within seven shots.
McIlroy, in his first appearance in the event, had two eagles, his second coming at the par-four 16th, his seventh hole, where his approach shot took a bounce and dived into the cup.
"Only shooting one-under yesterday on the south course, I knew I needed to go out and shoot something at least in the mid 60s to just make the cut, let alone get back in the golf tournament," he said.
"So it was nice to eagle the first hole we played and it's always a bonus when you can hole a wedge shot as well. All in all a good round of golf and at least have a shot going into the weekend."
Woods had only one blemish on his card, a double-bogey at his ninth, where his ball plugged in a bunker but he did not convert enough birdie chances to shoot better than 70 on the north course.
"It's going to have to be a special weekend to have a chance," said Woods, who needs two more PGA Tour victories to match Sam Snead's record of 82.
"I didn't make enough birdies. Iron shots weren't as close as I'd like to have them (although) I hit them in there close enough I should have made some of those putts."