ATLANTA (AP) -- Already established as the best player in golf, Rory McIlroy approached the FedEx Cup finale as though he had nothing to lose.
Except now he has so much to gain.
McIlroy was plodding along Saturday in the Tour Championship, frustrated by a pair of three-putt bogeys and a round that "wasn't much to look at out there" when his prospects changed quickly. He fired a 5-iron from 209 yards up the hill to 25 feet on the par-5 15th and holed it for eagle to tie Billy Horschel for the lead. McIlroy finished with a chip out of thick grass behind the 18th green to save par for a 3-under 67.
Horschel made two bogeys on the back nine and had to settle for a 69, still his 11th straight round in the 60s during the FedEx Cup, and still in great position to leave Atlanta with the biggest Sunday payoff in golf.
They were at 9-under 201.
And they had plenty of company in what was shaping up as perhaps the most enticing finish in the eight-year history of the FedEx Cup.
Jim Furyk, winless since he captured the FedEx Cup four years ago, had a 67 and was two shots behind. He would have to win the Tour Championship to have any chance of joining Tiger Woods as the only multiple winners of the FedEx Cup.
Another shot behind were Rickie Fowler (67), Justin Rose (66) and Jason Day (70).
Horschel was just trying to advance to the third playoff event when he was runner-up at the TPC Boston. He won the following week at Cherry Hills and came into the Tour Championship as the No. 2 seed. And now he is 18 holes away from a $10 million bonus and a five-year exemption on the PGA Tour.
"In the middle of the year, I'm not sure if you told me I would have a chance on Sunday to win the Tour Championship and possibly the FedEx Cup and do it while going up against the best player in our game right now ... no matter what happens, it's going to be an exciting day," Horschel said. "And hopefully, Rory and I can put on a great show."
McIlroy already has won two majors, the British Open and PGA Championship, sandwiched around a World Golf Championship. He kept reminding himself that he's already had the best year of anyone, a year most anyone would take over a $10 million bonus.
But now he is close to giving his big year the finish he thinks it deserves.
"I've come here with the ultimate goal of trying to cap it off and trying to put an exclamation point on it or the icing on the cake or whatever you want to call it," McIlroy said. "Would it be poetic justice? I'd feel really good about it."
McIlroy says he hasn't been playing his best, certainly not at the same level as Hoylake or Valhalla, where he won his two majors. But he was good enough. He three-putted the par-3 second hole, missing a 3-foot putt. He had to make a 4-footer to avoid his third four-putt in two weeks.
But all was forgotten with his eagle on the 15 and his tough par save on the 18th.
Horschel stretched his lead to three shots with a 6-foot birdie putt on No. 8 and matching two-putt birdies with McIlroy at the ninth.
Both players made bogey on No. 10, and McIlroy appeared to be in more trouble at the par-3 11th until the world's No. 1 player chipped to 8 feet and saved par, and Horschel missed his 15-foot birdie attempt.
"My short game really saved me today," McIlroy said. "I think the par putt on 11 was a big momentum putt in the round after three-putting 10 and Billy being in there pretty close and just narrowly missing for birdie. I think being able to hole that par putt was big."
The top five seeds at the Tour Championship -- Horschel is No. 2, McIlroy is No. 4 -- only have to win the Tour Championship to capture the FedEx Cup. This is the first time that two top-five seeds are in the final group of the final tournament of the year.
Furyk doesn't need to do the math. He only knows he has to win, and that was his priority after another year of close calls. Ditto for Fowler (No. 9) and Day (No. 10).
"Really all you can ask for going into the week is to be in a position to win Sunday," Fowler said. "The tournament is really going to start tomorrow on the back nine. I know pretty much most of the scenarios for me. I know if I win I've got a pretty good chance. I know there's some possibilities of some extracurricular activities if certain things line up properly."
He was referring to the most bizarre possibility of all - if Fowler and McIlroy are tied at the end of regulation, there would be a sudden-death playoff to determine who wins the Tour Championship. And if Fowler were to win the tournament in that case, there would be another playoff to decide the FedEx Cup and the $10 million.
Fowler first would have to make up three shots on McIlroy, which is not easy under any circumstances. And while McIlroy is running low on fuel, there's only lap left.
"Obviously, I know what comes along with the FedEx Cup and cash and all the rest of it," McIlroy said. "But I just want to win."