Americans Kenny Perry, Brad Adamonis and Eric Axley shared the lead on 15-under-par after the third round of the John Deere Classic on Sunday.
Jay Williamson, who fired a superb nine-under 62 to get within a shot of the leaders, was level on 14-under with joint overnight leader Will MacKenzie in Silvis, Illinois.
Mackenzie fired a one-under 70 after a double-bogey on the par-five 10th was offset by a round-saving eagle on the 17th.
J.P Hayes, who had a six-under 65, and South Korean Charlie Wi (69) were two shots off the lead and in contention along with South African Tim Clark whose 64 put him on 12-under.
With the world's top players in Europe preparing for next week's Open, Perry, whose rich run of form has brought him two Tour wins, is the only player in the field in the top 20.
