Jonathan Byrd carded a five-under 67 to take a one-stroke lead into the final round of the Wells Fargo Championship.
The 33-year-old began his round in poor fashion, with a bogey on the par-four first, and he followed successive birdies at the seventh and eighth with another dropped shot at the ninth at the Quail Hollow Club in Charlotte, North Carolina.
But Byrd stormed home on the back nine, with birdies at 10, 11, 13, 14 and 15 to move to 15 under, taking a one-shot lead ahead of overnight leader Pat Perez.
Matt Jones is the best of the Australians in a tie for 11th at eight under after a solid round of 69.
John Senden (six under) and Steven Bowditch (five under) both had to be content with rounds of 72 while Robert Allenby moved up to four-under after a 69.
Marc Leishman (71) and Jarrod Lyle (73) are both at one under the card while Mathew Goggin is even heading into the last round.
Perez shot a round of 70, and held the lead until a bogey at the 12th allowed Byrd to take over.
The American duo at the top are joined by another pair of home-grown golfers in the chasing pack - with Stewart Cink and Lucas Glover shooting 68 and 69 respectively to be tied for third on 12 under.
Argentine Andres Romero is locked on 11 under with Kevin Na and Bill Haas in a share of fifth, while England's Brian Davis is in outright eighth on 10 under.
World no.4 Phil Mickelson had been among the contenders, but he found the water with his tee shots at 15 and 17 to finish on seven under courtesy of his card of 74.