Justin Rose moved to the top of the leaderboard at the AT&T National with a stunning second round of 64 in Pennsylvania.
Rose relinquished a three shot advantage on the final day of the Travelers Championship in Connecticut last week, but put that disappointment aside with a bogey-free six under par 18 holes at the Aronimink Golf Club.
The 29 year old will head into Saturday's third round seven under overall - a shot ahead of South Korea's Charlie Wi and Australia's joint overnight leader Jason Day, who carded 65 and 69 respectively on Friday.
Rose said: "I think mentally probably it was one of my better rounds of golf. It just felt very patient. Even when I didn't hit a good shot, I accepted it.
"I didn't try to force the issue and get bullied by the golf course. So from that perspective things clicked today."
American pair Charley Hoffman (67) and Jeff Overton (68) were three strokes off the pace with World Number 14 Robert Allenby of Australia one of eight players tied for sixth a further shot back.
Day's fellow first-round leaders Nick Watney (71), Arjun Atwal (72) and Joe Ogilvie (72) slipped down the leaderboard after failing to match their Thursday exploits.
Tiger Woods' opening round of 73 had left the World Number One seven shots adrift after round one and in danger of not making the cut, but the defending champion's 143 total saw him squeeze into the weekend.
For the second day running, he was left frustrated by his putting.
"I drove the ball on a string the last two days and haven't gotten anything out of it," said the 34 year old.
"When you're not making any putts, what are you going to do? No matter how good I drive it, it doesn't matter; the putts aren't going in. I've just got to putt better."
Rose remained wary of Woods despite his ten shot cushion over the American.
"There's definitely a presence," he said. "If he gets charging and he gets near the top of the leaderboard, he still has a presence - no doubt about it."
