Luke Donald carded a 3-under 68 on Sunday and that helped him win the Dunlop Phoenix by five strokes.
Donald, who will return to No. 2 in the world thanks to the win, finished at 16-under-par 268.
Amateur Hideki Matsuyama, the 2010 Asian Amateur champion, closed with a 67 to take second at minus-11. Koumei Oda fired a 7-under 64 to grab third place at 10-under 274 at Phoenix Country Club.
Hiroyuki Fujita (70) and Brendan Jones (71) shared fourth place at minus-9.
Donald had a birdie and five pars through six holes. He eagled the par-5 seventh and followed with a birdie on the eighth to get to 17-under.
The Englishman stumbled to bogeys at nine and 10 as his lead was cut to three. Donald ran off seven straight pars from the 11th. He closed the tournament with a birdie at the last to seal the win.
Alvaro Quiros (68) finished in a tie for sixth. Gonzalo Fernandez-Castano (67), Jonas Blixt (68) and Shingo Katayama (72) were among five players tied for 10th. Ryo Ishikawa and Nicolas Colsaerts were among nine that shared 22nd at minus-1.