Hunter Mahan has won the Houston Open by one shot following a difficult day for former British Open champion Louis Oosthuizen.

Oosthuizen led the tournament by two shots at the beginning of the day but five dropped shots on the front nine ruined the South African's chances of heading into this week's Masters in winning form.

However, world number 14 Mahan produced a solid round of golf and a one under-par score was enough to take the title ahead of Carl Pettersson.

Although Mahan's accuracy of driving was inconsistent, the American's short game was of the highest quality throughout the round.

Petterson had two birdie chances in the last three holes to force a play-off but he failed in his attempts and Mahan held on for a tight victory with a tournament score of 16-under.

Elsewhere, Ernie Els's 12th-place finish means that he will miss the Masters tournament for the first time in 19 years.