Charley Hoffman, ice-cool on the back nine, took advantage of a last-day collapse by fellow American Ricky Barnes to clinch his fourth PGA Tour victory by one shot at the Texas Open in San Antonio.

Two off the pace overnight, Hoffman bucked a worrying recent trend of carding poor scores in final rounds as he closed with a three-under-par 69 on the challenging Oaks layout at TPC San Antonio.

The 39-year-old Californian recorded two birdies early on the back nine to break clear of a congested leaderboard, and then held steady before sinking his winning birdie putt from nine feet at the last to post a winning total of 12-under 276.

Compatriot Patrick Reed, who played with Hoffman in the final round, had to settle for second place as he also signed off with a 69, narrowly missing eight-foot birdie putts on 16 and 17 before finishing up with a birdie at the par-five 18th.

Padraig Harrington endured a disappointing day. The Irishman had played himself into contention with a third round 68 but he never reached those heights on the final round as four bogeys and just two birdies saw him finish on 5-under.