Scott finishes with a flourish in Atlanta

1 of 1 Adam Scott has to win the Tour Championship and hope that players ranked higher in the points standings finish poorly if he is to land the FedExCup and its $10million bonus

Adam Scott held a one-shot lead at the midway point of the Tour Championship in Atlanta after a superb recovery in his second round.

KJ Choi is second, with Jason Day and Luke Donald a further stroke behind.

It was, though, an awful day for the top three in the FedEx Cup standings with Webb Simpson, Dustin Johnson and Justin Rose all failing to make level par.

It means there is a possibility someone else can sneak in and claim the $10million bonus decided on an accumulated points system at FedEx Cup events.

Scott started the day in a five-way tie for fifth and he overcame a poor start, where he suffered three bogeys in the first six holes, to finish with eight birdies - including five in six holes - for a five-under-par 65.

Choi also finished with a five-under-par 65 with six birdies and one bogey.

Day matched his 67 of yesterday with five birdies and two bogeys to move to six under overall, while Donald putted two bogeys and four birdies for a two-under-par 68.

There was a four-way tie for fifth. Bubba Watson had started the day in 22nd but shot up the leaderboard with a six-under-par 64, including seven birdies and one bogey to finish at five under overall.

Three birdies on the final five holes helped lift Bill Haas alongside Watson after he improved on yesterday's 68 with a five-under-par 67 after three bogeys appeared to have scuppered him.

Hunter Mahan joined them following a two-under-par 68 in what is a consistent performance from the American.

Overnight leader Keegan made up the quartet following three bogeys and two birdies in his one-over-par 71.

Simpson led the FedEx Cup coming into the tournament but he produced five bogeys in the first 10 holes although a birdie and an eagle in consecutive holes on the back nine helped him to a level-par 70.

Johnson, second in the standings, also had an awful round with two double bogeys for a three-over-par 73.

BMW Championship winner Rose's round included two double bogeys, four bogeys and three birdies for a five-over-par 75.