The 55-year-old South African finished with a 4-under 68 at Fallen Oak for a one-stroke victory over 2011 winner Tom Lehman and second-round leader Kevin Sutherland.
Frost was penalized after his coin marking his ball on the green moved when he accidentally dropped the ball on it. That left him with a bogey, and he made a 5-foot par putt on the par-4 18th for a 10-under 206 total. After playing the front nine in 1 under with a bogey and two birdies, he birdied Nos. 11-13 to take the lead and made another birdie on No. 15.
Lehman closed with a 70, and Sutherland had a 72. Lehman had a chance to force a playoff, but missed a 4-foot birdie putt on the final hole.
Joe Durant was fourth at 8 under after a 69.
Lone Oak alum Kenny Perry shot a final round 69 and finished tied for 15th at 2 under. Paducah's Russ Cochran finished 70th at 13 over after a final round 74.
