Jesper Parnevik overcame an opening bogey to shoot a career best nine-under-par 61 at LaCantera Golf Course to open up a four stroke lead at the Texas Open.
Starting on the back nine, Parnevik bogeyed the 10th but quickly responded with a birdie at the 11th before carding five more to reach the turn at five-under-par.
Parnevik, looking for his first PGA Tour victory since the 2001 Honda Classic, added five more on the front nine, including back-to-back birdies to finish his round.
'I putted well all day. I hit two great shots into ten but came up short and didn't get it up and down and started with a bogey,' said Parnevik.
'But normally that's when the panic sets in a little bit, and you think you're going to have a really lousy day. I felt good about the game, good about the putter and I made birdie on the next hole and that was it.'
Robert Gamez, Justin Leonard, Mathias Gronberg, Bob Tway, Matt Hendrix, Neal Lancaster, Shigeki Maruyama, Daniel Chopra, Richard S Johnson and Dan Forsman are all tied for second at five-under 65.
Chad Campbell, who won the Viking Classic last week, is among a group of 12 a further shot adrift.
