Forsman sank a 22-foot putt on the final hole to finish a bogey-free 6-under-par 65 in the final round and 14-under for the tournament.

Forsman, who had not won since the 1992 Buick Open, finished one stroke ahead of defending champion Robert Allenby and Billy Andrade, who led after the first three rounds.

He said: "Instinctively, when you look up, you judge the speed of the ball and think, OK, that looks good.

"I had a sense in my heart that it was going to be a good putt."

Forsman also recorded birdies on the third, fifth, 10th and 15th holes.

"I didn't look at the leaderboard," he said.

"I knew I was keeping pace with the leaders.

"I felt if I could knock it on the [18th] green, maybe something crazy could happen."

Andrade needed to birdie the last for the fourth consecutive day to force a play-off, but his drive into a fairway bunker proved costly.

Allenby was in sole possession of first place before bogeying the par-5 14th.

His tee shot into the rough above the front bunker on the 17th - the site of his hole-in-one the previous day - cost him a shot at a repeat.