Graeme McDowell got off to a hot start on a cool, damp day Friday, finishing with seven birdies in a six-under 66 for a three-shot lead in the Tiger Woods-hosted World Challenge.

Northern Ireland's McDowell had a 36-hole total of nine-under 135 at Sherwood Country Club, where 18 golfers are chasing a first prize of $1 million from the total purse of $4 million.

Bo Van Pelt, Jim Furyk and Keegan Bradley shared second on 138. Van Pelt posted a 68 while Furyk and Bradley both carded 69s.

Woods, who hosts the unofficial event for the benefit of his charitable foundation, thrust himself into contention with a run of four birdies in five holes starting at the ninth.

But he lost some traction with his second bogey of the day at 15 and signed for a three-under 69 for 139.

McDowell won this tournament in 2010, capping an outstanding season that included his US Open triumph up the Pacific coast at Pebble Beach.

He hasn't won since, and admitted it would be nice to punctuate a season in which he finished equal second at the US Open and tied for fifth at the British Open with a win -- even in a non-tour tournament.

He started quickly at Sherwood Country Club with three straight birdies. After his lone bogey of the day at the par-four seventh, McDowell added four more birdies coming in on a course softened by overnight rain and further dampened by intermittent misty showers on Friday.