Michael Putnam fired a 9-under 62 Thursday to grab a share of the lead after the opening round of the Boise Open.

Putnam, the 2010 Utah Championship winner, was joined atop the leaderboard by Andrew Svoboda and Tyrone Van Aswegen.

Glen Day and Jeff Gove are one stroke off the lead at minus-8.

Luke Guthrie, who turned pro earlier this year, and Sam Saunders, Arnold Palmer's grandson, share sixth place at 7-under 64.

Of the 156 players that teed it up on Thursday, 104 broke par as Hillcrest Country Club averaged 69.4 strokes, the lowest first-day number in tournament history.

Putnam started on the back nine and got on the board with birdies at 10 and 13. He birdied the par-5 15th to move to 3-under.

The 29-year-old Putnam poured in five consecutive birdie chances starting at the 18th. After that spurt, he parred four of the last five holes to go with a birdie at the seventh to post a 62.

"It was as easy as it's ever played. Zero wind and a perfect temperature," said Putnam. "Today everything felt comfortable. I was never in between clubs and even if I was, I didn't feel I was in between shots. That's what happens on days like today."

Svoboda, who is 11th on the tour's money list, birdied two of his first three holes from the 10th. He followed a birdie on the par-5 16th with another at 18 to make the turn at minus-4.

The 2-time runner-up this season eagled the par-5 second and came right back with a birdie on the third to get to minus-7. Svoboda birdied the seventh and ninth to grab a share of the lead.

Van Aswegen played the front side first and flew out of the gate with an eagle on the second. After a birdie on the fourth, he poured in three straight birdies from the sixth.

Around the turn, Van Aswegen birdied the 10th to move to 7-under. He cooled off with four straight pars before carding birdies at 15 and 17 to move into a tie for the lead.

"This is probably the best weather we've had all year. There was no wind all day long. The greens were pure. Just put it on your line and the ball's going to go in the hole," Van Aswegen stated.

NOTES: Defending champion Jason Kokrak stumbled to a 2-over 73...Last week's winner, Robert Streb, is tied for 81st at minus-1...Casey Wittenberg and Luke List, who are first and second on the tour's money list, both shot 4-under 67, while No. 3 Ben Kohles is tied for 12th at minus-5...Andy Bare had a hole-in- one on the par-3 17th...Jeff Klauk, who made his first start in 14 months, opened with an even-par 71...Casey Martin carded a 3-under 68 and is tied for 39th in his first tour start since 2006.