ATLANTA (AFP) - Bill Haas parred the third hole of a sudden-death playoff on Sunday to defeat fellow American Hunter Mahan and win the US PGA Tour Championship as well as a $10 million season playoff bonus. Haas, who made a jaw-dropping escape from water on the second extra hole, took home $1.4 million for the event victory plus the $10 FedExCup bonus, winning more money in one day than his father Jay won in his entire PGA career. Mahan settled for $1.5 million in runner-up and bonus money after losing the richest one-hole showdown in history and the longest playoff in the 25-year Tour Championship history. After saving par on the 17th in the playoff with a chip shot to an elevated green, Haas was in fairway short of the green on the third playoff hole, the par-3 18th, while Mahan found a bunker right of the green. Mahan blasted 15 feet past the cup while Haas putted to within four feet. Mahan rolled his par putt three feet past the cup and Haas sank his putt to win a kings ransom, raising his right fist in victory. Haas entered the 30-man, season-ending event 25th in points but finished on top, 15 ahead of American Webb Simpson, who led entering the week. World No. 1 Luke Donald of England was third, 103 points back. The playoff began at the par-3 18th with Haas hitting into the grandstand and dropping in the rough. Mahan followed by finding a right front bunker. Haas chipped to 10 feet and sank the putt while Mahan blasted out to six feet and parred to extend the playoff to the par-4 17th, where Haas made a miraculous rescue. After finding a fairway bunker, Haas put his second shot left off a 10-foot plateaued green and just into the edge of a water hazard while Mahan found the center of the green 25 feet from the cup. Haas blasted his third shot to a stop four feet from the cup, the crowd roaring in approval, and each man parred to set up the last playoff hole. Haas knew he needed an amazing shot as he looked at the ball nestled in a thin layer of water atop a sandy bed. Mahan and Haas finished 72 holes on eight-under 272, one shot ahead of Donald, Australian Aaron Baddeley and South Koreas K.J. Choi. Aussies Jason Day and Adam Scott and American Charles Howell were on 274. Tiger Woods won the season playoff points crown in its 2007 debut and 2009. Fijis Vijay Singh took it in 2008. US veteran Jim Furyk won it last year. Haas was helped by his father and mother walking with him as spectators all week. Haas, who lost two prior playoffs this year, was playing in the Tour Championship for the first time. It was the 16th playoff in the US PGA season, matching the record total from the 1988 and 1991 seasons. Haas birdied the par-5 15th but bogeys at the 16th and 18th left him level for the lead with Mahan, who birdied the par-5 15th and parred in to force the playoff, and Day, who birdied 11 and 15 but closed with back-to-back bogeys. Donald hit an eight-foot birdie putt at the par-3 18th, his third birdie in the final five holes, to keep himself in with a hope of the $10 million until the last putts of regulation. Simpson, the season playoff points leader when the week began, fired a 73 to finish 22nd on 282. His hopes went to the last putts as well but for him to collect the $10 million he needed Baddeley to win the tournament.