Dufner rolled in a 25-foot putt on the final hole Sunday to win the Byron Nelson championship in Texas by a stroke over Dicky Pride.
The 35-year-old Dufner, who was born in Ohio, started golfing as a boy in Florida, played at Auburn and turned professional in 2000, climbed seven places in the world rankings.
Dufner's other recent win was April 29 at the Zurich Classic of New Orleans.
Rory McIlroy still has the No. 1 spot in the rankings
Martin Kaymer dropped out of the Top 10 and is now No. 11, followed by Webb Simpson (12), Adam Scott (13), Dufner, Louis Oosthuizen (15), Charl Schwartzel (16), Jason Day (17), Graeme McDowell (18), Dustin Johnson (19) and Rickie Fowler (20).
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