American Matt Kuchar carded a seven-under 64 to take an early lead after the first round of the BMW Championship in Chicago on Thursday.
A dropped shot on the eighth hole was the only blip for Kuchar, who stormed home with two birdies and an eagle on the last four holes to take a one-stroke lead over compatriot Ryan Moore at Cog Hill.
Kuchar currently tops the FedEx Cup points standings after winning the first playoff tournament, The Barclays, in late August and a win in Chicago would give him a massive lead ahead of the Tour Championship in Georgia in a fortnight.
Moore bogeyed twice in the first five holes, but hit a remarkable seven birdies in the back nine, including five-in-a-row to the 18th, to hold second place outright ahead of Englishman Ian Poulter, who fired four birdies and an eagle after the turn to finish with a five-under 66.
Tiger Woods dropped two shots on the first hole and never regained that ground, finishing the opening day two-over and tied for 45th place.
Woods bogeyed again on the sixth but started the back nine with a par and two birdies before dropping a shot on the 12th.
The world No.1 saved a shot on the par-three 14th and parred his way to a bogey on the 18th for a round of 73, his first since being handed one of US captain Corey Pavin's four wildcards for the Ryder Cup.
Only the top 30 players in the FedEx Cup points standing after this weekend get to play in the Tour Championship at East Lake in Georgia in a fortnight, and Woods is in danger of missing out on the lucrative tournament currently sitting in 53rd.
It was a tough opening round for the Australians with Matt Jones and Adam Scott the best placed at even-par.
Marc Leishman, Greg Chalmers, Robert Allenby, Michael Sim and Jason Day, who bogeyed three of his first four holes are all a shot behind, while Geoff Ogilvy shot a 73 to be two-over.
South African Retief Goosen and South Korean Charlie Wi tied for fourth on 67, while English duo Luke Donald and Justin Rose finished on three-under 68 and a tie for sixth with Americans Dustin Johnson and Brian Gay.
Goosen's compatriot Rory Sabbatini dropped three strokes in the front nine but found form after the turn, hitting consecutive birdies on 11 and 12, eagling the 15th and saving a further stroke on the last to finish two-under and tied for 10th with Englishman Paul Casey.
Deutsche Bank Championship victor Charley Hoffman, who sits second on the FedEx Cup points list behind Kuchar, leads a field of 15 tied for 12th place on one-under par.
World No.2 Phil Mickelson finished a stroke over on after carding a 72.