Tiger Woods surged into a three-way tie for the lead in the Wachovia Championship second round.
The world number one, seeking his first victory at the tree-lined Quail Hollow Club, fired a four-under-par 68 in chilly, overcast conditions to finish on six-under 138.
That left Woods level with 2005 champion Vijay Singh, who recovered from five bogeys in an erratic outward nine to shoot a 71, and American Arron Oberholser, who birdied his last three holes for a 69.
Two more Americans, Ted Purdy (69) and Jason Bohn (72), were a further stroke back in fourth place.
Overnight pacesetter Padraig Harrington held a share of the lead with one hole remaining before triple-bogeying the difficult par-four 18th for a 75 to slip back to three under.
The Irishman, who found water at the last with his second shot and three-putted from 15 feet, experienced a roller-coaster day which included three bogeys in his first four holes and a four-birdie run from the 10th.
Woods, playing his first tournament since tying for second at the Masters three weeks ago, felt he got the most of out of a round that featured five birdies and a bogey at the par-four ninth, his final hole.
