World No.1 Adam Scott is three shots off the lead at the Colonial event on the US PGA Tour, as he tries to hang on to the top spot.
Scott picked up three strokes on his inward run to post a two-under 68 on Friday that left him on one-under for the tournament.
Scott, who supplanted the injured Tiger Woods atop the world rankings on Monday, capped his round with a 23-foot birdie putt at 18.
The Australian’s first stint as world number one could prove to be short-lived.
He can be overtaken this week by Sweden’s Henrik Stenson, who is playing in the European PGA Championship in England.
Rookie Brice Garnett had three birdies and an eagle in a four-under 66 to take a one-stroke lead at the halfway stage.
Garnett had a seven-under-par total of 133, with Chris Stroud and Robert Streb a stroke back on 134 and seven players – including Australian Aaron Baddeley – sharing fourth place on 135.
That group at five-under included first-round leader Dustin Johnson, who carded a 70, and South African Tim Clark, who birdied four holes in a row from the 12th en route to a 68.
Baddeley (67), England’s Brian Davis (67) and Americans Bo Van Pelt (68), Chad Campbell (66) and Jimmy Walker (68) were also in the group on 135.
Garnett, whose only mis-step was a bogey at the par-four third hole, continued a strong run of play in Texas. He notched his first top-10 PGA Tour finish six weeks ago at the Houston Open, where he finished with a share of seventh.
“For some reason, it’s just I’ve kind of adapted to Texas golf,” he said. “Growing up back home in the spring and fall, it gets pretty windy as well. I kind of relish whenever the wind blows … kind of got to control your ball.”
Stroud’s round included eight birdies. He made five putts from outside 20 feet, four of them coming in his final nine holes.
“Man, it sure is nice to make putts,” Stroud said. “I was so relaxed out there. It was obviously a little luck.
“But the key is every putt I hit today, I hit really, really solid,” added Stroud, who drained a monster 56-footer for birdie at the par-three fourth.
While Johnson wasn’t able to maintain his spot atop the leaderboard, he said his even-par 70 wasn’t bad.
“Just didn’t hole the putts,” he said. “Got a couple of bad kicks. Other than that, I played pretty solid again today.”