Mike Heinen fired an eight-under par 63 to take the first round lead at the John Deere Classic in Illinois.

The 35-year-old American matched the best round of his career as he bids for his first PGA win since 1994.

He is hoping to take advantage of an under-strength field as the majority of the tour's stars are taking a week off after playing in last week's Open Championship.

Heinen shot nine birdies and made a solid start in quest of his first title since the 1994 Houston Open.

He lies two strokes ahead of Tripp Isenhour, Robert Gamez and defending champion David Gossett.

"I hit the ball real well," Heinen said. "I don't even know how many fairways and greens (I hit), but I hit a lot of them and gave myself a lot of opportunities."

Spike McRoy, who won his first PGA title last week, and fellow American Duffy Waldorf, who shared the lead after the first round at Muirfield last week, were among 10 players who fired a 66 to share fifth.

Heinen played the first five holes at three-under, then pulled his tee shot off a tree at the 226-yard seventh hole.

He did not need much time to recover with a birdie at the eighth hole.

He then made five more on the back nine to match the round he recorded at the 1995 Buick Challenge.

Scores from the first round of the PGA Deere Classic (USA unless stated):

63: Mike Heinen
64: Fred Funk
65: David Gossett, Robert Gamez, Tripp Isenhour
66: David Berganio, Duffy Waldorf, Gene Sauers, Pete Jordan, Michael Long (Nzl), Mark Carnevale, Spike McRoy, Jerry Smith, Jeff Gove, Peter Jacobsen, Nolan Henke, Lucas Glover
67: Miguel Angel Jimenez (Spa), Hidemichi Tanaka (Jpn)
68: Richard Zokol (Can), Edward Fryatt (Gbr), David Frost, Bradley Hughes (Aus), John Senden
70: Eduardo Herrera (Col)
72: Grant Waite (Nzl), Rod Pampling (Aus), Mathew Goggin (Aus), Mathias Gronberg (Swe), Steve Allan (Aus)
73: Wayne Grady (Aus), Esteban Toledo (Mex)
74: Paul Gow (Aus)
76: Gabriel Hjertstedt (Swe)