American Bryson DeChambeau carded a superb eight-under 64 to take a two-shot lead at the halfway point of the Safeway Open PGA tournament.
DeChambeau climbed seven spots on the leaderboard in completing a second bogey-free round to go with his 68 from Thursday, his Friday performance comprising a front half of three-under 33 and a homeward nine of five-under 31.
The 26-year-old birdied six out of eight holes between the fifth and the 12th, and hit 15 of 18 greens in regulation.
At 12-under par he led by two shots from countryman Nick Watney, who fired a 65 to follow a 69.
Watney was one shot clear of a five-way tie for third place including Canada's Nick Taylor and South Africa's Dylan Frittelli.
Italian Francesco Molinari slipped down the leaderboard with a second round 71 which put him in a tie for 10th, as did Australian Adam Scott, who followed a strong 65 with a 73.
