He used two long birdie streaks, shot a 9-under 63 over the final 18 holes, and finished at 22-under 266, one shot better than Jerry Kelly.
Triplett opened the round with five consecutive birdies, bogeyed No. 7, and then made birdies from 14-17 to grab the lead. Kelly -- who made four birdies on the front nine and drained a 25-foot putt for birdie at 13 -- was the runner-up at 21-under 267.
Third-round leader Duffy Waldorf held the lead on the front nine, but made only one birdie at the par-five 10th, and then bogeyed 16 to end tied for third at 19-under 269 with 2004 champion Heath Slocum (68) and Bubba Watson (70).
Watson became the first player to go 72 holes without a bogey in a PGA event since Lee Trevino at the 1974 Greater New Orleans Open.
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