Chris Stroud moved to the top of the leaderboard at the Texas Open on day two, shooting a six-under-par 64 for a two stroke lead at the halfway mark.
Stroud began the second round in a tie for 10th on four under after an opening 66 at the Resort Course at La Cantera Golf Club and continued his good form with seven birdies and a lone bogey to improve to 10 under.
Stroud birdied the first hole and bogeyed the second but was nearly flawless from then on, picking up three more birdies before the turn and making another three on the back nine to move two clear of Paul Goydos, Tim Petrovic and Tim Herron.
Goydos shot a four-under 66 for the second straight day, Petrovic turned in a five-under 65 and Herron delivered a 67 as the trio reached the midway point at eight under.
Kevin Streelman enjoyed the best round of the day, firing a seven-under 63 to move into a tie for fourth with a group of nine players including Australia's Matt Jones (64) and South Africa's Rory Sabbatini (66).
Nathan Green of Australia, who held the opening round lead after an impressive eight-under 62 dropped into a tie for 41st after a disappointing 75 while defending champion Justin Leonard barely made the cut after carding a 69 to reach one under.