Northern Ireland's Rory McIlroy was level par after nine holes of the first round of the Tour Championship, trailing early clubhouse leader Justin Rose by four shots.
McIlroy bogeyed the first hole before picking up a birdie on the third at East Lake in Atlanta, with Rose carding a 66 to set the clubhouse target. American Scott Piercy had reached five under par after 16 holes but ran up a double-bogey five on the 18th to card an opening 67.
McIlroy's partner Tiger Woods completed the front nine in two under par, picking up shots on the second and third and recovering from a bogey on the fourth with a birdie on the par-five ninth, where McIlroy failed to get up and down for birdie from just off the green.
The Tour Championship is the last leg of the FedEx Cup play-offs and McIlroy and Woods are paired together again because they are first and second in the points standings.
It is winner-take-all between them despite McIlroy storming to victory in the last two tournaments.
In fact, the top five on the table - Nick Watney is third, Phil Mickelson fourth and Brandt Snedeker fifth - all know that if they win on Sunday they not only take the tournament first prize of nearly £900,000, but also the FedEx bonus of more than £6.1million.
And such is the system that all 30 players in the field, including McIlroy's Ryder Cup team-mates Lee Westwood, Luke Donald, Rose and Sergio Garcia, all have a chance of scooping the bonus payment.
Rose, who carded two bogeys and six birdies - the last of them a curling, long-range effort on the 18th - said: "I scrambled well, my bunker play was sharp.
"I only hit seven fairways but it shows it comes down to chipping and putting and these greens are so good that when you hit the line they go in."