Arron Oberholser just misses shooting 59 - EDS Byron Nelson Championship 2006

Oberholser shot a sparkling 10-under-par 60 - just the 17th in PGA Tour history - to move within four shots of the leaders after Friday's second round of the $6.2 million Byron Nelson Championship.

Oberholser needed only 22 putts as he shattered his previous best round of 64 and took the spotlight away from Brett Wetterich and Adam Scott, who are tied for the lead at 10-under-par 130.

"It was a fabulous putting round," Oberholser said. "It was arguably the best putting round of my PGA Tour career, without a doubt."

The Tour record is 59, done in official events three times and most recently by David Duval in the final round of the 1999 Bob Hope Chrysler Classic.

The most recent 60 came in the second round of the 2005 Players Championship by Phil Mickelson, who aso fired a 59 in the 2004 Grand Slam of Golf, an unofficial event.

After signing for a 4-over 74 in Thursday's opening round, Oberholser posted an immaculate bogey-free round Friday, making four birdies on the front nine and six more on the way in.

The 30-year-old Oberholser, who picked up his first career victory earlier this year at the Pebble Beach National Pro-Am, is more than pleased with the progress he has made this season.

"I think I'm improving," said Oberholser, who made his 11th straight cut. "My consistency is getting better. I'm focusing more on the mental aspect of the game than I have been. I'm learning - I know the golf courses now, this being my fourth year. I'm settling in."

Oberholser's best stretch of the day came when he birdied the first four holes on the back nine, making a pair of 25-foot putts and a 20-footer. After birdies at Nos. 16 and 17, he had a chance for a magical 59 but missed a 15-footer on the par-4 18th.

"Walking to the (18th) green, man, I had a smile from ear to ear. It's just so cool," Oberholser said. "It's the best nervous you can be because it's exciting. It's the same - you're just soaking it in."

In all, Oberholser birdied nine of the final 14 holes.

Wetterich carded a 6-under 64 that included seven birdies and only one bogey. He never has placed better than his fourth-place finish at the Zurich Classic earlier this year.

The first-round co-leader, Scott signed for a bogey-free 65. The Australian native is in search of his fourth career title and first since 2004.

"It was solid ball-striking today," Scott said. "I had a few more chances that I probably left out there, but it was pretty solid golf and I'm happy to go bogey-free."

Steve Lowery, who also was tied for the lead after the opening round, battled through and inconsistent day that included six birdies and five bogeys, leaving the veteran tied for fifth at 6-under 134.

World No. 4 Vijay Singh shot a 67 to move into a tie for 14th, seven shots off the pace.

Defending champion Ted Purdy finished his second round two shots ahead of the cut line, carding a 69 to enter the halfway point at 1-under 139.