Alex Cejka shot a 5-under 67 to move to 15 under and take a two-stroke lead after Saturday's third round at the Turning Stone Resort Championship.
Chris Couch tied the course record with a 63 and was alone in second place at 13 under. Billy Mayfair birdied six holes on the front nine and was in third place at 12 under after a 66.
Charles Warren, Bill Lunde, Robert Garrigus and Chris Tidland were tied for fourth place at 11 under. Warren recorded the first 63 of the day after he had seven birdies and eagled the par-5 12th hole in a bogey-free round. Peter Lonard set the course record at the 2009 Turning Stone Resort Championship when he carded a final-round 63.
Cejka, from the Czech Republic, is trying to become the first foreign-born winner in the four-year history of the event.
International players have won 11 of the last 15 PGA Tour events. Cejka -- the second-round leader -- is winless in 227 previous starts on the PGA Tour. He has finished second twice.
"I still have to go out there tomorrow and try hard and try to shoot a couple under," Cejka said. "I cannot rely on my two-shot lead and trying to go out there and just shoot even par. I don't think that would do it."
Sunshine, mild temperatures and a gentle breeze left the 7,482-yard Atunyote Golf Club almost defenseless. Just three of the 72 players that made Friday's cut shot over par.
Cejka had a shaky start on the second hole, where he three-putted for just his third bogey of the week. He recovered with a birdie on the par-4 fourth with a second shot that spun back to tap-in range. On No. 5, he reached the par 5 in two and two-putted from 28 feet for another birdie.
Cejka's next birdie came on another par 5 at No. 12. This time he laid up 77 yards short of the green with his second shot and landed his third three feet from the hole.
Cejka got to 13 under with a birdie putt from inside seven feet on the par-3 16th. His second shot on 17 ended up less than four feet from the cup for another birdie as he became the first player to reach 14 under. At the 615-yard closing hole, he was on the back fringe in two and two-putted for his sixth birdie of the day. He hit 17 greens in regulation.
"I'd rather be two in front than four behind," Cejka said. "Doesn't matter what happens tomorrow. The others will have to come, too, but it's always nice to have the lead. It doesn't matter by how many."
Cejka played his first PGA Tour event in 1996 and is competing in his 228th event, but has never won. He finished second at the 2004 International and tied for second at the 2003 B.C. Open. This marks the third time in his career he has held the 54-hole lead, including the 2001 British Open. He has 11 international victories.
"I think in the past I was struggling a little bit with the putter the first couple holes when I had the lead, and suddenly the lead was gone after three, four holes because you make one bad shot, you make a three-putt and suddenly someone makes a birdie and you're not in the lead," he said. "I hope I learned something out of it in the past and it will show tomorrow."
Mayfair has improved his score each day after he opened with a 70 and followed with a 68 on Friday. He has the most success of anyone in the top seven with five victories and 15 runner-up finishes in 23 years on the PGA Tour. However, his last win was in 1998, when he finished on top at the Nissan Open and the Buick Open.
"It was a great temperature out there," Mayfair said. "The golf course is in great shape, and it was definitely conditions for some good scoring. I took advantage of it on the first nine holes. I didn't play as good on the back, but six under, I'll take it."