Keegan Bradley maintained his three shot lead at the HP Byron Nelson Championship by following up his stunning opening round of 60 with a one under par 69 in Texas.
The American Ryder Cup star, who had four birdies and three bogeys in his second round at TPC Four Seasons Resort, will head into the weekend with compatriot Tom Gillis (63) and South Korea's Bae Sang-moon (66) as his closest challengers.
"I'm almost more proud of this round than yesterday because I didn't feel comfortable all day," Bradley said.
"I don't know what it was. I can't put my finger on it... I was a little uncomfortable and then I settled it and hit some really good shots.
"It was hot, the wind was blowing a little bit... it was difficult out there. It was actually a tough round, mentally, to play. I wanted to stay in there - it was just a weird spot I've never been in."
The 26 year old, who won this tournament in 2011, continued: "I'm happy with the way I played.
"I'm giving myself really good chances here. All my putts are going down m line, which is a really good sign for the weekend.
"I'm excited to play. I love this course. I'm focusing on winning this tournament now. I'm in a good position and I've been here and done it before, so it's a good omen to have."
Bradley leads the way on 11 under - despite having twice bogeyed the par four first hole - and acknowledged his 36-hole total could have been even lower.
"The first hole is probably the easiest hole out here," he said. "I don't know why I keep making bogey on that hole."
The 2011 Masters Tournament champion Charl Schwartzel was a further stroke adrift after signing for a second round 70, tied for fourth along with American pair John Huh (64) and Ryan Palmer (68).