The victory was the sixth of his career, and one of the most important.
Mahan had gone 48 tournaments worldwide without winning and began the FedEx Cup playoffs at No. 62, guaranteed to play only two events. By closing with a 6-under 65 for a two-shot victory, he is assured of making the Tour Championship every year since the FedEx Cup began in 2007.
And by beating one of the strongest fields of the year, Mahan was sure to make a lasting impression on Tom Watson for when he makes his three captain's picks for the Ryder Cup on Sept. 2.
“To get a win in an event like this and the timing, it feels unbelievable,” Mahan said. “So I'm extremely proud of myself. I felt great the last few weeks. My game was starting to come around. I knew this was around the corner, but to do it — and to do it today with a 65 — feels great.”
On a day when six players had at least a share of the lead, Mahan found a way to make it look like a comfortable win.
He rolled in a 10-foot birdie putt to take the outright lead on the par-3 15th, hit wedge to 3 feet for a birdie on the 16th and then rolled in a 20-foot birdie on the par-5 17th. That stretched his lead to three shots going to the final hole when Cameron Tringale bogeyed the 18th, and Mahan tried to inject a little drama.
Mahan drove into the trees, pitched out and then missed the green. But he holed an 8-foot putt for bogey.
Jason Day, who shared the 54-hole lead with Jim Furyk, would have needed to hole out from the rough on the 18th to force a playoff and he missed the green. Day closed with a 68 and shared second place with Stuart Appleby (65) and Tringale, who celebrated his 27th birthday with a 66.
Furyk now has failed to win the last eight times he has held at least a share of the lead going into the final round. He was in the mix until missing the fairway on the 14th and taking bogey, and he wound up with a 70 to finish in eighth place, four shots behind.
Mahan finished at 14-under 270 and earned $1.44 million. He moved to No. 1 in the FedEx Cup standings, assured of being among the top five players at East Lake with the best shot at capturing the $10 million bonus.
British Open and PGA champion Rory McIlroy, going after his fourth straight victory, closed with a 70 and tied for 22nd.
Scott Dunlap beats Mark Brooks in Boeing Classic playoff
Scott Dunlap won the Champions Tour Boeing Classic when he made a short birdie putt on the first hole of a playoff against Mark Brooks.
Dunlap set up his winning putt on the par-5 18th hole with an outstanding approach to the right of the pin that bounced past the hole, and then drew back downhill to within four feet. He missed his eagle try but made his next putt for his first Champions Tour victory.
Brooks, who put himself in jeopardy by landing in a bunker on his drive, just missed a 30-foot putt on his fourth shot. It was the fifth playoff in the 10-year history of the tournament at TPC Snoqualmie Ridge.
Jamie Donaldson secures Ryder Cup spot
Jamie Donaldson shot 4-under 68 Sunday to win the Czech Masters and secure a spot on the European Ryder Cup team.
Tied for second with Soren Kjeldsen overnight, Donaldson took the lead when his Danish opponent made two straight bogeys on the last two holes of the front nine. The Welshman surged further ahead with two birdies on the first three of the back nine.
Donaldson birdied six holes and dropped two shots for a total 14-under 274 in windy conditions at the Albatross Golf Resort near Prague for his third European Tour victory after the Irish Open in 2012 and Abu Dhabi Golf Championship in 2013.