Chris Riley shoots 66 to upstage big guns in Ohio

American journeyman Chris Riley made a mockery of his poor record at the Memorial tournament by charging into an early one-shot lead in last night's opening round.

On a sun-splashed day at Muirfield Village Golf Club where Riley has missed the cut in his three previous starts, the 37-year-old fired a sizzling six-under-par 66. He recorded eight birdies and two bogeys on the undulating, heavily wooded layout to upstage some of the biggest names in the game.

Chris DiMarco birdied five of his last eight holes for a 67 to lie one shot off the pace with fellow American Josh Teater.

British world No 1 Luke Donald recovered from an opening nine of two-over 38 to card a six-birdie 70 while fourth-ranked American Phil Mickelson returned a 72. But Riley, who claimed his only PGA Tour victory at the Reno-Tahoe Open in 2002, took the greatest advantage of a relatively calm morning in the event hosted by Jack Nicklaus to soar into the lead.

Donald, who became world No 1 for the first time with a play-off victory over fellow Briton Lee Westwood in the European Tour's PGA Championship on Sunday, salvaged his round with five late birdies. His low point came with a double-bogey at the par-4 18th, his ninth hole, where his approach ended up in a bunker and he needed two more shots to reach the green.

"I hit a great 8-iron right at the pin and it came up maybe two yards short of being perfect and kicked back in the middle of the trap," Donald said. "I just got a little bit too cute. "I hit a poor bunker shot, another poor chip and lipped out the (bogey] putt. So taking four from literally 20 feet wasn't what I was hoping for."

Holder Justin Rose, who won last year by two shots, launched his title defence with a 71.