Zach Johnson fired a six-under-par 64 in the final round to claim a two-stroke victory at the Texas Open.

Entering the day a shot off the pace, Johnson had seven birdies and a bogey to finish at 19-under 261, two strokes ahead of three players who tied for second.

Charlie Wi carded a bogey-free nine-under-61 to share second on 17-under 263 alongside Mark Wilson and Tim Wilkinson.

Johnson started with a birdie but it was cancelled out by a bogey at the second. He had three consecutive birdies starting at the sixth and he picked up another birdie at the 10th.

Johnson led by one after a birdie at the 14th and he came to the 18th tee needing just a par to clinch his first win since the 2007 AT&T Classic. He did one better, clinching the win with a birdie.

Defending champion Justin Leonard came up short in his bid for a fourth title here. He fired a 66 yesterday to finish at 11-under 269

Some time off and a return to basics were key to the success, according to Johnson.

"I made the commitment, I had six weeks off or seven, whatever it was, since New Jersey," said the 2007 Masters champion. "Much of that was forced off and some of it was choice.

"I made the commitment to go back to what I used to do, the way I'm supposed to do it and ball-striking and putting, and I didn't anticipate hitting me this quick but, you know, it certainly helped.

"Given that, I still see a lot of room for improvement which I guess is even more encouraging than anything else."

Entering the week, Johnson had just one top-10 finish this season. He had not played since missing the cut at The Barclays to start the FedEx Cup play-offs, making his performance this week a bit unexpected.

"I had two things in my mind this week as far as going into the week and one was no expectations," Johnson said. "So, no, I did not expect to be here but I guess that's a good thing.

"The second was just to - you know, I made some commitments to my fundamentals, to my golf swing and starting to pay-off. So it's very encouraging."

Collated final round scores & totals

(USA unless stated, par 70):

261 Zach Johnson 69 66 62 64

263 Charlie Wi (Kor) 67 68 67 61, Tim Wilkinson (Nzl) 67 69 63 64, Mark Wilson 68 66 66 63

265 Jeff Overton 69 64 67 65

267 Chris Stroud 66 64 69 68, Stephen Ames (Can) 68 71 66 62

268 Rory Sabbatini (Rsa) 67 66 63 72, Pat Perez 71 64 68 65, Tim Herron 65 67 67 69

269 Justin Leonard 70 69 64 66, Tim Petrovic 67 65 68 69, Greg Kraft 65 71 65 68, Harrison Frazar 69 69 65 66

270 Dustin Johnson 67 69 68 66, Jeff Maggert 73 65 64 68, Shane Bertsch 69 69 66 66, Bob Tway 66 72 64 68

271 Chris DiMarco 68 69 70 64, Steve Allan (Aus) 66 70 71 64, Kevin Streelman 70 63 69 69, Bob Sowards 68 70 70 63, Joe Durant 68 67 72 64, Paul Goydos 66 66 73 66, Chad Collins 65 73 65 68, Jimmy Walker 67 66 69 69, Jason Gore 65 74 66 66

272 Michael Thompson 68 65 67 72, Steve Elkington (Aus) 68 70 73 61

273 Nathan Green (Aus) 62 75 70 66, Joe Ogilvie 66 67 67 73, Brian Gay 68 67 69 69, Tag Ridings 66 70 69 68, Mark Hensby (Aus) 68 66 67 72, Troy Matteson 68 70 66 69

274 Jason Allred 68 66 74 66, David Toms 68 66 70 70, Nick O'Hern (Aus) 65 72 70 67, Charles Howell III 68 67 68 71, Chez Reavie 67 67 69 71, Chad Campbell 71 65 68 70, Jhonnathan Vegas 69 67 69 69, Scott Verplank 68 66 70 70

275 Patrick Sheehan 65 71 70 69, Michael Bradley 66 70 67 72, Todd Demsey 66 70 69 70, Dean Wilson 71 67 69 68, Bob Estes 68 68 69 70, Bo Van Pelt 68 70 67 70, Carlos Franco (Par) 69 70 67 69, Craig Kanada 69 65 70 71, John Riegger 68 69 67 71

276 Nick Watney 67 71 69 69, Steve Marino 68 69 69 70, Douglas Labelle 69 69 68 70

277 Kevin Stadler 67 66 69 75, Olin Browne 64 69 74 70

278 Paul Claxton 64 70 72 72, Robert Gamez 70 68 73 67, Richard S Johnson (Swe) 70 67 70 71, J J Henry 70 68 70 70, Vaughn Taylor 70 68 67 73, Sean O'Hair 72 66 70 70

279 Brad Elder 68 69 73 69, Jim McGovern 67 70 66 76, Alejandro Canizares (Spa) 66 73 70 70, Tom Pernice Jnr. 70 69 68 72, Matthew Jones (Aus) 69 64 73 73

280 Scott Sterling 69 70 72 69

281 Charley Hoffman 68 69 71 73, Martin Laird (Sco) 67 71 71 72

282 Frank Lickliter II 69 66 70 77

283 J.L. Lewis 68 69 68 78, Nicholas Thompson 72 67 72 72

285 Kyle Thompson 66 69 71 79