South Africa's Rory Sabbatini and American Steve Marino were tied for the lead after the first round of the BMW Championship at Cog Hill, Illinois.

The pair fired five-under rounds of 66 to lead by one from American Bo Van Pelt and Australian Marc Leishman.

Padraig Harrington and Tiger Woods carded 68s, while Ian Poulter took 69 and Luke Donald signed for 70.

The 70-strong field are playing for 30 spots at the season-ending Tour Championship later this month.

The final event in the Fed Ex Cup play-off series, limited to the top 30 in the list of points accumulated throughout the season, carries a first prize of $10m (£6m).

Sabbatini, who missed the cut in the first two events in the FedEx Cup play-offs, joined Marino in birdieing the final hole for the lead.

"I obviously didn't play very well the last couple of weeks," Sabbatini said. "These things tend to break out of their cycles and it was nice to get out there today and actually have a nice, fun, relaxing round of golf.

"I drove it very well and on this course that's key, because since the redesign they've made it a lot more of a chess game around the greens."

The Tour Championship is scheduled for East Lake Golf Club in Atlanta, Georgia from 24-27 September.