Aaron Baddeley fired a six-under 64 Saturday to grab a share of the lead after three rounds of the Tour Championship.
Hunter Mahan, who clinched his spot on the U.S. Presidents Cup team last week, posted a four-under 66 at East Lake to join Baddeley atop the leaderboard after 54 holes.
They are tied at nine-under-par 201.
"The Presidents Cup is a big deal. We all want to make it as players," Mahan said in a televised interview. "To think about that for the few weeks going in (to the playoffs) and the way guys were playing, they just made it so tight eight through 12 (in the standings). It was a load off to get that off my mind."
Baddeley is battling to earn one of Greg Norman's two captains picks for the International team at the Presidents Cup.
He is 14th on the International points list, and the three players ahead of him -- Louis Oosthuizen, Tim Clark and Robert Allenby -- are not in the field this week. Clark has been out of action with an elbow injury.
"Coming into the week, the Presidents Cup was on the forefront of my mind," Baddeley admitted. Talking to Greg on Monday, I knew I had to play well this week to impress him. So I did a lot of work Tuesday and Wednesday, especially on my putting, and I'm very pleased so far this week."
Jason Day, who tops the International team points list, managed a one-under 69 and is tied for third with K.J. Choi at minus-seven. Choi had two bogeys and two birdies in an even-par 70.
Bill Haas grabbed a piece of the lead twice on the back nine, but dropped three strokes over the last two holes to tumble back to six-under 204. Haas carded a one-under 69, and he was joined there by world No. 1 Luke Donald, who posted a 70.
Phil Mickelson (67) and Fredrik Jacobson (68) share seventh place at minus- five. Second-round leader and 2006 champion Adam Scott struggled to a four- over 74 to slide into a tie for ninth at four-under 206.
Along with the race for this title and a spot on one of the Presidents Cup teams, players are also battling for the FedEx Cup title. Webb Simpson entered the week atop that points list, but he stands at minus-one after his second straight round of 70.
The way things stand after 54 holes, Mahan, who is 21st on the points list, would jump over Simpson into the top spot and win the $10 million top prize.
However, Baddeley will have something to say about that as they head to the final round.
Baddeley, who started the week 27th in the race for the FedEx Cup, traded a birdie for a bogey from the second. He followed that with a hole-out eagle on No. 4 while birdies on the seventh and ninth got him within one of Scott's lead.
When Scott bogeyed the fifth, Baddeley was suddenly tied for the lead with his countryman. Baddeley tripped to a bogey on No. 11 after his tee shot found a greenside bunker.
Baddeley atoned for that error with a six-footer for birdie at the 13th to join Mahan and Scott atop the leaderboard at minus-seven.
Mahan jumped into the mix with a birdie on No. 8 and a 22-foot eagle putt at the par-five ninth. That gave him the lead at minus-eight, but a poor bunker shot at 10 led to a bogey.
The 29-year-old Mahan drained a 19-footer for birdie at 11 to briefly go one up at minus-eight, but Baddeley joined him there with a 22-foot birdie chance on No. 14.
Baddeley moved into the lead by himself with a 21-foot birdie effort at the 15th and came right back with a six-footer for birdie on 16, moving him two ahead at minus-10.
Mahan dropped a shot on 13, but responded with a birdie 15 to get back to minus-eight.
Baddeley's run of four consecutive birdies stopped on the 17th, where he drove into a fairway bunker and missed the green with his approach. Baddeley chipped to 22 feet, but two-putted for bogey to slide to minus-nine.
"In recent months, I haven't holed that many putts, so it was nice to be able to make some putts," Baddeley said. "I did a lot of work this week on my putting, so I feel like it's definitely paying dividends right now. The putter feels really good."
After a pair of pars, Mahan poured in a 22-footer at the last to join Baddeley in the lead at minus-nine.
NOTES: Baddeley has won two of the six times he owned at least a piece of the 54-hole lead...Mahan owned a piece of the third-round lead for the first time in his PGA Tour career...If Donald can rally to win this title, he has a chance to become the first person to ever lead the PGA Tour money list and the European Tour Order of Merit in the same season.