In a battle of generations Sunday at Riviera, the 29-year-old Baddeley played mistake-free over the final six holes to hold off Vijay Singh and deny a fairy-tale finish for 51-year-old Fred Couples.
"I thought Freddie was going to be tough today because winning is a skill, and Freddie has been winning quite often recently," Baddeley said. "When he got off to a good start, I was like, 'Freddie looks like he's going to have one of those days where he's going to play great.' I was still just trying to focus on my game, and try to do what I needed to do."
Baddeley closed with 2-under 69 for a two-shot victory over Singh, who turns 48 on Tuesday.
It was the third career PGA Tour win for Baddeley, who had plunged to No. 224 in the world.
This isn't enough to get back into the top 50, but at least he can book a trip to Augusta National in April for the Masters Tournament.
Singh, who only three weeks ago had fallen out of the top 100 in the world for the first time in more than 21 years, had his highest finish since he won the Deutsche Bank Championship in 2008 on his way to the FedEx Cup. Despite back-to-back bogeys on the back nine, he gave himself a chance to the end and closed with 69.
Singh said it was the best week with the putter in his career, which would include his 2000 Masters victory. He took only 105 putts for the week, including just one three-putt in the second round.
The heartache belonged to Couples.
Two decades after he last won at Riviera, Couples ran off three consecutive birdies to start his round and take the lead. But it all came crashing down with a double bogey on the seventh hole -- where Baddeley made a 20-foot birdie -- and Couples never caught up.
"I just didn't feel the same after that," Couples said. "I didn't really hurt myself, but I never hit a shot, and I just got it around."
Couples bogeyed two of the last three holes for 73 and wound up in a tie for seventh.
Baddeley, who finished at 12-under 272, won for the first time since the 2007 Phoenix Open.