Goosen has now taken a personal best three victories for the season, including earlier wins at the United States Open and Scottish Open at Loch Lomond.
His total earnings of 2,801,351 euro ($2,498,805) throughout the year make him the first non-European winner of the money race since Australian Greg Norman did so in 1982.
Additionally, he became the first South African winner of the prestigious title since Dale Hayes in 1975.
It didnt come easily on Sunday at Club de Campo, however. Goosen was pushed all the way by 25-year-old Steve Webster of England.
After a strong start, the youngster recorded a late birdie at the par-5 15th to tie Goosen at 20-under-par with just three holes to play.
Goosen gained the edge a short time later, however, at the par-3 17th, when he canned a birdie to move to 21-under.
Seemingly on his way to outright victory, the South African proceeded to miss the fairway at the closing 18th, and then hit his approach shot short of the green and into a bunker.
Unable to get up-and-down, his bogey saw him close with a 68 and he fell back into a tie with Webster, who parred the last for a 66 and joint-first at 20-under 264.
On the first extra hole (that same 18th), Webster had a great shot of winning, but just missed a birdie putt from only five feet.
Following two more pars on the second extra hole, Goosen came to the spot of his last birdie in regulation at the par-3 17th.
Playing a 9-iron, the smooth-swinging Goosen hit his tee shot to eight-feet, and he followed suit by draining the birdie for the win.
After the dramatics, he was brutally honest about the state of his game.
I didnt play well all week, he claimed. My putter saved me.
His win might have saved him from Darren Clarke, who had been nipping at his heels on the money list all season.
Clarke closed in 67 on Sunday to finish tied for sixth at 16-under. His earnings for the week saw him solidify his position of second on the season-long list, but in the end, gave no real threat to catching Goosen.
Said Retief of the year: Darren Clarke left me with no option but to play this week after he entered, and its nice to win this tournament and pull off the Volvo Order of Merit for the first time.
I have a long way to go to catch Montys seven victories in a row, but I regard this as a great honor.
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