Jim Furyk fired a seven-under-par 65 to take the lead with Phil Mickelson in the Pebble Beach National Pro-Am second round.
The world number two birdied his last three holes to complete a bogey-free display at Poppy Hills Golf Club, one of three venues being used for thisweek's PGA Tour event.
Furyk ended a damp and overcast day on the Monterey Peninsula at 12-under 132, three strokes ahead of fellow Americans Kevin Sutherland (63) and John Mallinger (70).
Sutherland and Tour rookie Mallinger, who was joint leader overnight with twice champion Mickelson and Nick Watney, both played at Spyglass Hill.
Masters champion Mickelson, after an indifferent outward nine of one-under 35, rattled up birdies at the 11th, 13th, 14th and 15th.
Of the other big names, 2004 champion Vijay Singh was five under for his round with four holes to play at Poppy Hills and Irish world number nine Padraig Harrington three under after 13 holes at Pebble Beach.
Mallinger, who earned his 2007 Tour card by tying for 13th at last year's qualifying school, was the only player in the field of 179 professionals to remain bogey-free after two days.
"I think I'm a steady player and I'll take 70 out there every time," the 27-year-old Californian told reporters. "It's a tough course. I thought it was playing a little longer today with the rain and everything and it was hard to get the ball back at the flag."
Davis Love III, another double winner at Pebble Beach, was a further two shots back at seven under after shooting a six-birdie 67 at the hosting Pebble Beach Golf Links.
The pro-am field play each of the three venues over the first three days before the leading 60 professionals and ties qualify for Sunday's final round on the Pebble Beach Golf Links.
