Bubba Watson has won the World Golf Championship after a tense playoff victory over Tim Clark in Shanghai.

Graeme McDowell had taken a slender one-shot lead into the final day, but he carded a final round of 74 as he fell away to finish third alongside Hiroshi Iwata and Rickie Fowler.

Watson almost threw away a winning position himself on the back nine as he posted a bogey on the 16th and a double-bogey on the 17th to surrender his lead.

Another poor shot on the final hole saw him land his approach shot in a greenside bunker, but he kept his composure to drop a wonderful chip into the cup for an eagle.

He then entered a playoff with the consistent Clark, who posted his third round of 69 in the tournament with a composed display.

However, when he could only make par on the extra hole, Watson rolled a birdie putt in to win in dramatic style.