Goosen had a three-stroke lead over Singh trimmed to a shot after 12 holes before pulling away for his third PGA Tour victory and first of the season.
The African finished with a 1-under 70, giving him a 72-hole total of 12-under 272, three shots better than Singh and four ahead of Briny Baird.
It was the 17th title worldwide for Goosen, the 2001 U.S. Open champion.
Singh has won twice and finished second twice in his last four starts. He boosted his lead over Woods in the money race to more than $750,000. If Singh finishes among the top three at the Tour Championship next week, he will win the money crown no matter what Woods does.