Justin Leonard fired his best round of the year showing signs of ending a two-year win drought by grabbing to grab a share of second place at the $3m PGA Kemper Open at Potomac, Maryland.

The 1997 British Open winner and Kemper champion fired a six-under par 65 but cost himself a share of the lead with fellow Americans Jay Williamson and Steve Lowery by calling a one-stroke penalty on himself that no one else saw.

Leonard had a two-foot birdie putt on the 13th hole when he looked down and saw the ball resting on his putter. He took a one-stroke penalty for moving the ball and settled for par.

Ireland's Keith Nolan lies nine strokes off the lead after shooting 73.