(CNN) -- Veteran Kenny Perry charged to the top of the Tour Championship leader board with a six-under 64 at East Lake to overtake world number one Tiger Woods.
Perry acknowledges another birdie in his superb third round at East Lake.
The 49-year-old American will take a two-shot lead into the final round as Woods struggled to a one-under 69 in the final event of the PGA Tour's FedEx Cup series.
Woods was expected to cruise to victory to clinch the £10 million on offer for the series, but Perry gatecrashed the party in spectacular style.
"When you open up with four birdies in a row, that don't happen a lot, especially on this golf course," Perry told reporters.
"I knew it was going to be a special day.
"I had such a good feeling, a good vibe, after those first four holes. I was relaxed and I knew it was going to be a good day."
Perry, who was one of the heroes of the U.S. Ryder Cup triumph last year in Kentucky, will need similar inspiration when paired on the final day with Woods, chasing his seventh victory on the PGA Tour this season.
Woods, who is six-under overall on 204, is still confident of sealing victory.
"I feel good, I just need to hit a few putts," he said.
Arch rival Phil Mickelson may also have a say after continuing his improvement with a four-under 66 to be four-under overall, four shots back and in a tie for third with first round leader Sean O'Hair (70).
Ireland's Padraig Harrington began the day a shot behind Woods, tied with O'Hair for second, but carded four bogeys against three birdies in a 71 to lie five shots off the pace at three under, alongside American Steve Marino, who carded a 67.
World number two Steve Stricker, who started the tournament second in the FedEx Cup standings, is at two under after improving with a fine 66.
Stricker is tied for seventh with South Africa's Ernie Els, who carded a 71 to slip down the field.