World number one Rory McIlroy birdied his final two holes to earn a four-way share of the clubhouse lead in the first round of the BMW Championship, while playing partner Tiger Woods was a shot back.

McIlroy, fresh off his win at the Deutsche Bank Championship on Monday, mixed an eagle, seven birdies and a lone bogey for an eight-under 64 at Crooked Stick Golf Club.

That put him atop the leaderboard with Americans Webb Simpson and Bo Van Pelt and Canadian Graham DeLaet. 

Van Pelt, who failed to land a spot on the US Ryder Cup team this week, may have had captain Davis Love III rethinking his picks after a bogey-free round while Simpson, an automatic selection to the squad, was equally impressive, particularly on the back nine stringing together four consecutive birdies from the 14th.

Woods and McIlroy, the only players with three PGA Tour wins this season, were paired together and offered fans an intriguing side-by-side comparison of golf's two most intriguing figures.

Joined by American Nick Watney, the threesome garnered most of the attention from spectators on a sweltering hot day in the American Midwest as Woods and McIlroy went toe-to-toe producing a scintillating display of quality shot making.

While Holywood's McIlroy and American Woods will do battle later this month for national honours at the Ryder Cup it was each man for himself on Thursday as an elite field of 70 players are vying for one of 30 spots in the Sept. 20-23 Tour Championship finale in Atlanta where the overall points winner gets a $10 million bonus.

McIlroy, in top form after winning two of his last three starts, arrived at the PGA Tour's penultimate FedExCup playoff event leading the points standings.