Ireland's Padraig Harrington is leading the European challenge after the second round of the Buick Open in America.
The 29-year-old shot a second successive 67 to move to 10-under-par and into a tie for fifth - four shots behind leader Kenny Perry.
A blistering run on the back nine, where Harrington claimed five birdies in seven holes, brought him home in five-under-par 31 and shot him up the leaderboard.
Frenchman Jean van de Velde, who was well placed after an opening 66, fell back with a one-under-par 71.
Perry, without a tour win in six years, carded an eight-under-par 64 on his 41st birthday to open a three-shot lead at the halfway point.
He leads a group including first-round co-leader Jim Furyk, Bob Tway and Brett Quigley. Perry said: "It was a great day for me.
"I told my caddie after three holes my game's ready to win. I felt like I was going to make a lot of birdies," he added after equalling the Warwick Hills Golf and Country Club's front nine record of 29.
Furyk, who can clinch a Ryder Cup spot with a victory this week, was unable to follow up his first round 64. Nursing a wrist injury for nearly a year, Furyk settled for a three-under 69.
Furyk nearly completed his second straight bogey-free round until reaching the 197-yard par-three 17th.
He has not missed the cut in seven appearances at Warwick Hills and shares the course record with a 62.
Tway and Quigley began the day four strokes off the pace, but carded 65s to climb from a tie for 22nd. A total of 32 players are within five shots of the lead.
Phil Mickelson, the world number two and Tom Pernice Jr, coming off a victory at The International, are among those tied for 10th place at 135.
Mickelson began the day one shot off the pace, but settled for a two-under 70. Pernice followed up a first-round 68 with a 67. AFP