The South African claimed the $2m winner's cheque - the richest ever prize in world golf - with a birdie at the second sudden-death play-off hole.

Describing his winning putt from four feet, Els likened the nervousness he felt to the feeling of being in contention to win a major.

"I don't know how I took the putter back," he said. "I knew it was an inside right putt, but to get it on line... I'm still shaking now.

Vital putt

"I think it was the most nervous I've ever been. I can state that now."

Els and Westwood had finished the four rounds tied on 20-under par 268.

They both parred the first extra hole - the 16th - before Els came out on top at the 17th after Westwood had missed his birdie chance.

Asked how he had felt putting to win $2m, Westwood said: "Well, you don't get them very often.

"It (the money) didn't really cross my mind, to be honest. I was just trying to win the tournament."

Take your chances

The Englishman added: "Ernie hit a great shot into 17 and I followed him in, but it was just on the limit for a wedge, so it was always going to get a bit too much spin.

"I actually hit it to about 15 feet, but I just missed it. You've got to take your chances when they come."

Westwood picked up $300,000 for finishing second while Zimbabwe's Nick Price and Denmark's Thomas Bjorn, who tied for third on 269, earned $225,000 each.

Els became the fourth player in the 20-year history of the tournament to retain the title, after Seve Ballesteros, David Frost and Price.