Dufner stands at 18-under-par 198. Pat Perez is at 16-under following a 68. Todd Rose (66) and David Gossett (66) are tied for third at 15-under.
Dufner is making just his second career start on the Buy.Com Tour. The 2000 Auburn University graduate qualified for the U.S. Open, but failed to make the cut. He Monday qualified for last weeks event in Hershey and tied for 12th; that earned him a spot in this weeks field.
Saturday, Dufner recorded nine birdies and one bogey.
Full-field scores from the Buy.Com Wichita Open