Zach Johnson turned around an overnight deficit to win the Texas Open by two shots after firing a final round of 64.
The 2007 Masters champion had seven birdies and a bogey for a six under par score, finishing on 19 under overall to secure his first victory of 2008.
Korea's Charlie Wi who had a nine-under 61, tied with Mark Wilson and Tim Wilkinson for second on 17 under.
Defending champion Justin Leonard came up short in his bid for a fourth title as he carded a 66 to finish 11 under.
Meanwhile, overnight leader Rory Sabbatini slipped to 12 under after hitting a two-over-par 72.
"This hasn't been the best year for me," said Johnson, who had only one top-10 finish coming into the event. "It's been a long time coming.
"I've been working on my putting over the last six weeks with my teachers and it really paid off this week.
"I had a tough year, but the putts started to fall today and that's why I'm at the top of the leaderboard."
Johnson started well with a birdie at the first but immediately cancelled it out by conceding a bogey at the second.
He made up for that disappointment with three consecutive birdies starting at the sixth and he picked up another at the 10th.
Johnson led by one shot after the 14th and he came to the 18th tee needing just a par to clinch his first win since the 2007 AT&T Classic.
But he sealed the win with a five-foot putt to give him his first win of this season.
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