Rory McIlroy remained in a good position on a crowded leaderboard midway through his second round of the Tour Championship in Atlanta on Friday.
McIlroy carded three birdies and one bogey on the front nine at East Lake to move to three under par, three shots off the lead shared by Australian Jason Day and American Billy Horschel.
Along with Chris Kirk, Bubba Watson and Hunter Mahan, Horschel and McIlroy are the five players who know victory on Sunday would also see them win the overall FedEx Cup title - and with it a bonus of £6million.
McIlroy insists the title means more to him than the money, the 25-year-old keen to end a brilliant season on a high note after four victories, including two major titles in the Open and US PGA Championship.
The world number one holed from 11 feet for his first birdie of the day on the second but bogeyed the fourth for the second day in succession after his drive plugged in the face of a fairway bunker.
McIlroy had been frustrated by taking one step forward and one step back on Thursday, but this time took two steps forward with birdies from close range on the sixth and seventh, although another birdie chance did go begging on the par-five ninth.
Horschel, winner of the BMW Championship last week, had made the ideal start with birdies on the second and third to move to six under, while Day had birdied the first, fourth and fifth.
McIlroy never threatened to hole birdie putts on the 10th or 11th, but very nearly holed his approach to the 12th, his ball clattering into the pin.
Fortunately for the Northern Irishman it finished just eight feet away and he holed the putt to move to four under and into a share of second place, two shots behind Day.
Horschel, who has vowed to stay and fight for the £6million bonus even if his wife goes into premature labour, had bogeyed the fifth and seventh to drop back alongside McIlroy, Kirk, Ryan Palmer and Jim Furyk.
Despite a run of just one birdie in nine holes, McIlroy's round was proving far from uneventful, with his wayward drive on the 14th clipping a tree and falling into a spectator's shorts pocket.
After somewhat warily taking a free drop, McIlroy was left with a clear shot to the green and made a safe par, while he had to save par from a greenside bunker on the 16th after another errant tee shot.
At four under he remained two off the pace set by Day and Kirk, Kirk having moved to seven under with four birdies in succession from the seventh before a bogey on the 11th.
The best round of the day so far had come from England's Justin Rose, a 66 taking the former US Open champion to two under par overall.