Henrik Stenson continued his fine form to open up a four-shot lead at the Tour Championship in Atlanta while a nightmare finish from Tiger Woods saw the world number one fall out of contention.
Stenson had held the overnight lead at six under and a second round 66 saw him move to 10 under, with Masters champion Adam Scott his nearest competition.
The Swede got off to a flying start as he made birdies at the first, second, fourth and ninth meaning he had played the front nine in just 61 shots over the first two days.
He went on to drop a shot at the 10th but a further birdie 16 saw him go into the weekend with a comfortable cushion.
The Swede knew that a win here would secure him the first prize of 1.4million US dollars and the 10million US dollars bonus for winning the FedEx Cup.
Woods, Scott, Zach Johnson and Matt Kuchar can also claim both prizes with a win this weekend but that now looks a near impossibility for Woods, who had looked on course to make one of his trademark charges before his round fell apart.
The 37-year-old, who has five wins on tour this year, responded well to Thursday's disappointing 73 and was five under for his round through 13 holes.
But a double-bogey at 14 followed by another dropped shot on 16 and a treble-bogey on 17 saw him drop to four over for the tournament, 14 shots behind Stenson.
That had put the 14-time major champion in last place before Jason Dufner, Brandt Snedeker, Boo Weekley and Charl Schwartzel all slipped behind him.
"I put everything I had into that start and didn't have much at the end," Woods told www.pgatour.com. "Just ran out of gas. My legs were just tired.
"It's been just a long, long grind. We play a lot of golf from the British Open on."
Scott endured a rocky front nine but two birdies to go with two dropped shots got him to the turn in par and a birdie at 16 had him out in second place on his own.
Jordan Spieth was a further shot back after firing a three under par 67 with Justin Rose, Dustin Johnson and Billy Horschel all sat on four under.
Keegan Bradley and Nick Watney both fired 65s to sit in the group at three under alongside Zach Johnson while Kuchar was three over following a disappointing 74.
Englishman and former world number one Luke Donald shot a second successive round of 70 to sit level par.
Tournament organisers also announced that due to expected rain and possible thunderstorms on Saturday, players would be in threesomes for the third round and the first tee time had been brought forward to 7.30am local time (12.30pm BST).