Alex Cejka signed for a five under 67 to take a two stroke after the third round of the Turning Stone Resort Championship.
Cejka held a one stroke lead overnight, but enhanced his advantage with a round which featured six birdies.
Chris Couch (63) was alone in second on 13 under, with Billy Mayfair (66) one stroke further back and four players four shots off the lead on 11 under.
Cejka, who is chasing his first US PGA Tour win in 227 events, was on ten under overnight, but dropped back with a bogey five on the second.
However, that was the only blemish on the German's scorecard as he added six birdies.
Cejka recorded successive birdies on the fourth and fifth, added another at the 12th, before ending his round with three straight gains.
Couch carded nine birdies in his bogey-free round.
He made a birdie three on the second and added three more on the front nine before a run of four straight birdies from the 12th and a final flourish on the 18th.
Mayfair also had a bogey-free round, with all six of his birdies coming on the front nine.
Charles Warren equalled Couch's day-low round, with seven birdies and an eagle, to sit on 11 under alongside three others - Bill Lunde (64), Robert Garrigus (68) and Chris Tidland (70).
Five shots off the lead entering the final round were Scott McCarron (64), Brett Wetterich (67), Michael Bradley (68), Charley Hoffman (68), Woody Austin (69) and Rory Sabbatini (71).
