Flesch made an 18-foot eagle putt on the par-5 fourth to get to 4 under through four holes. He made the turn at 6-under 30 and got to 8 under when he hit a 3-wood within 10 feet for another eagle on the 584-yard 11th. He birdied from 4 feet on the final hole of his bogey-free round that was one stroke off the course record and one in front of Jose Conceres.
'If I ever had a chance to shoot 59, it would have been today,' said Flesch, who has two wins in 11 years on tour and more than $13 million in career earnings.
'It's probably the best I've played in the last five years out here on tour. Every hole I had a chance of making birdie. But I'm certainly not complaining about 9 under,' said the 40-year-old left-hander from Kentucky who has three top-10 finishes in eight previous appearances at the 7,472-yard Montreux Golf & Country Club on the edge of the Sierra Nevada.
Conceres had six birdies, a bogey and a hole-in-one on the 220-yard seventh in his 64. He said the ace was extra special because it came on the 16th birthday of his daughter, Maria Jose, who was home in Argentina.
'It was a very good score for my daughter,' Conceres said. 'I hit a 6-iron straight at the hole and I was very lucky that it wound up in the hole.'
Steve Allan, who missed a 4-foot bogey putt on the last hole that would have won the tournament in 2004, and PGA rookie John Merrick were at 65.
Defending champion Will MacKenzie, former University of Nevada golfer Charlie Wi and Jason Gore had 66s. Corey Pavin, Bob Tway and Lucas Glover were in a group of eight at 67. Notah Begay III, winner of the inaugural Reno event in 1999, shot a 68.
Tadd Fujikawa, a 16-year-old Hawaiian making his pro debut, double-bogeyed his first and 10th holes in struggling to a 6-over 78.
Dialed in all day with his irons, Flesch hit 17 greens and the fringe of the other one, leaving him on average inside 18 feet of the pin. He missed a 5-foot birdie attempt on the first hole and a 3-footer on No. 5. He also missed an 8-foot birdie attempt on 14 and a 6-footer on 17 that would have given him a share of the course-record 62 that Bill Glasson set in 2005 and Joe Ogilvie tied last year.
Flesch said he doesn't remember the last time he had two eagles in the same round.
'Putt-Putt, probably,' said Flesch, whose best finish this year has been a tie for fifth last month at the U.S. Bank Championship in Milwaukee. He is 132nd on this year's money list with $406,586. He expects low scores through the weekend if the wind doesn't pick up and the greens remain soft.
'It's going to be the `O.K. Corral' out here. It's going to be a shootout,' he said.
MacKenzie birdied his first three holes despite a minor crisis that playing partner Rich Beem helped solve on the opening green.
'I get out there and I don't have anything to mark my ball with,' MacKenzie said. He asked his caddie and girlfriend for help, but no luck.
'So I said, `Hey, Beemer. You got any coins on you?'' said MacKenzie, an avid kayaker, surfer and snowboarder whose victory in Reno last August was his first on tour.
'He had lots of them. I picked out a 1963 nickel that's all black. It was probably his favorite. It was old school. But he's fired up after the third birdie in a row. He said, `I want that nickel back,'' MacKenzie said.
On the par-5 4th, MacKenzie sent a 60-foot birdie attempt rolling toward the cup.
'Beemer was like, `If that putt goes in. ...' I was going to be injured going to the next hole,' MacKenzie said. 'But anyway, he didn't ask for his nickel back. I've got it and I putted well so maybe I'll keep if for the week, unless he sees me at the craps table and he wants it back.'