Spieth makes his move in Atlanta

Jordan Spieth overtook Henrik Stenson with a closing birdie to take a one-shot lead at the Tour Championship on Saturday.

The 21-year-old did not have the best start at a rainy East Lake Golf Club, and was one over par through eight holes of his third round and not making much ground on Stenson, who was maintaining his advantage.

But Spieth made his first birdie of the day at the long ninth, however, and then added another at the next par-five, the 15th, before saving par with a 20-foot putt at the 16th.

Stenson, meanwhile, was even par through his first nine holes courtesy of one birdie and a bogey, but he slipped up after the turn, bogeying the 10th and 11th holes to allow Spieth to get within touching distance.

The Swede birdied the 14th to regain some of his lost ground, but bogeyed the 17th to sign for a disappointing two-over-par 72.

His playing partner Spieth was having far less trouble, and birdied the final hole courtesy of another 20-foot putt for a two-under-par 68 and a two-shot swing at the end of the day, ensuring that he will start the final round in pole position as he chases the lucrative $10million bonus for winning the FedEx Cup.

Should Spieth go on and win on Sunday, it would cap a truly stellar season for the young Texan, who also captured successive major titles at the Masters and US Open earlier in the year.

He would also leapfrog Rory McIlroy and current world number one Jason Day at the top of the world rankings.

"I'm very pleased with where we stand going into tomorrow, and Henrik's going to come back very strong," Spieth said. "This was his off day, and so I'm going to have to play even better."

Stenson is still feeling good about his chances as well, despite not having the best day.

"Kept it together fairly nicely and we're still at the races," Stenson said. "I would have liked to have gone a few better, but we're still up there and yeah, it's all going to be decided tomorrow."

While it is looking like a shoot-out between Spieth and Stenson for the title on Sunday, there are others still in with a shout.

Rickie Fowler (67) and Paul Casey (71) share third place on four under, four shots behind Spieth and three behind Stenson, while Rory McIlroy (70) follows on three under alongside Open champion Zach Johnson and will need something special to overcome a five-shot deficit.