Sergio Garcia mastered windy conditions to card a second round one-under-par 71 and retain his two-shot advantage at the Wachovia Championship in Charlotte, North Carolina.
The first-round leader mixed three birdies with a pair of bogeys to move to seven-under 137 through 36 holes, a couple of shots ahead of three players, including world number two Vijay Singh.
Back in action for the first time since winning the US Masters last month, Tiger Woods mixed five birdies with five bogeys for a level par round that left him five shots off the lead on two-under 142.
Garcia produced a steady and patient performance, particularly during a bogey-free back nine, in gusting winds that had many players scratching their heads.
"As well as I played yesterday, you always come out there thinking, 'let's see if I can do something similar'," he said. "But the course was playing a bit tougher today and it was a lot windier.
"Some of those fairways are almost impossible to hit. It felt good to go out there and only make two bogeys and make a couple birdies here and there.
Singh made a flawless start to his round and was four under through 12 holes before faltering slightly over the closing stretch, mixing a pair of bogeys with a birdie for a three-under-par 69.
At the halfway stage, the Fijian is in a tie for second with Americans D.J. Trahan and defending champion Joey Sindelar on five-under 139.
Sweden's Richard S Johnson and Americans Brett Quigley and Scott Verplank are a shot further back at four-under 140.
Ireland's Padraig Harrington carded a 75 after an opening round 71 and is nine shots off the lead.