Rory McIlroy’s defence of his FedEx Cup title was damaged by a one over par round as Marc Leishman shot nine under in round one of the BMW Championship.
McIlroy is 51st in the FedEx Cup standings and needs to be in the top 30 to reach next week’s Tour Championship, where the winner gets a $10m bonus.
But six dropped shots led to a round of 72 at Illinois’ Conway Farms Golf Club.
Australia’s Leishman hit 10 birdies to lead compatriot Jason Day and American Charley Hoffman by two shots.
Leishman dropped just one shot and looked in fine touch all day, hitting 79% of fairways and 89% of greens. He was five under after his opening nine holes and picked up four more birdies on a bogey-free back nine.
It was a continuation of fine form this year which has seen him win the Arnold Palmer Invitational in March and make the cut in all four majors. As the season draws to a close, the 33-year-old has six top-10 finishes on the PGA Tour.
That form sees him seventh in the FedEx Cup rankings prior to this week’s event, where players seek points to make it to the final Tour event of the season, next week’s Tour Championship in Atlanta.