American Ben Curtis fired a blistering nine-under-par 62, his lowest score on the PGA Tour, to take early control at the Booz Allen Classic in Potomac, Maryland.
Despite missing a nine-footer at the last for his sixth birdie in a row, Curtis finished the opening round at the TPC at Avenel three strokes clear of compatriots Steve Flesch and Will MacKenzie.
Curtis, whose only PGA Tour title came with his surprise victory in the 2003 British Open at Royal St George's, made a fast start with four consecutive birdies from the par-five second.
Out in four-under 32, he then produced a five-birdie run from the par-five 13th to eclipse his previous lowest round on the PGA Tour by two strokes.
Left-hander Flesch, who teed off at the par-four 10th, caught fire on his homeward nine, reeling off three birdies and an eagle-three on the way to a blemish-free 65.
Australia's Craig Parry bogeyed his final hole, the par-three ninth, for a 67 to finish level with Americans John Huston, Chris Smith and Chris Couch, winner of the New Orleans Classic in April.
Rich Beem, the 2002 U.S. PGA champion, returned a 69 while Ireland's Padraig Harrington, the highest-ranked player in the field, opened with a 70 that include five birdies and four bogeys.
