(CNN) -- Henrik Stenson increased his lead to four shots at the Tour Championship on Friday as the race for the $10 million FedEx Cup jackpot heats up.
The Swede was once again on song in the second round firing an impressive four-under 66 to finish on 10-under at the halfway stage.
Stenson and four other players (Tiger Woods, Adam Scott, Zach Johnson and Matt Kucher) can all claim the $10 million FedEx bonus if they win at Atlanta's East Lake Golf Club on Sunday.
Australia's Adam Scott is still Stenson's nearest challenger after following up his opening round of 65 with a composed 69 on Friday. But Tiger Woods' chances faded dramatically in the closing stages of his second round.
The world No.1 was five-under par for his round after 13 holes and looked to have repaired much of the damage inflicted by an opening 73. But the wheels well and truly fell off in the remaining five holes.
A hooked tee shot at 14 led to a double bogey six which was followed by a bogey two holes later. Worse was to come at the par four 17th when Woods pulled his tee shot into the water before holing out for calamitous triple-bogey seven.
"I put everything I had into that start and didn't have much at the end. Just ran out of gas." Woods said, PGATour.com reported.
"My legs were just tired. I didn't rotate through the ball (at the 17th), and I turned it over. Same thing I did over on what was it, 14? Same shot," Woods added.
"It's been just a long, long grind. We play a lot of golf from the British Open on."
A five-time winner this season, Woods didn't rule himself out of the running immediately after finishing, saying "this is not a sprint. It's a marathon."
Following Stenson's second round, Woods now requires a minor miracle to make up a 14-shot deficit, but further up the leaderboard others are ready to pounce should the 37-year-old Swede falter.
America's Jordan Spieth is a shot behind Scott in third after firing a three-under 67 while Justin Rose's second successive 68 left him tied for fourth at four under with America's Dustin Johnson (68) and Billy Horschel (70).
Keegan Bradley and Nick Watney both shot rounds of 65 to move up in to a five-way tie for seventh alongside Steve Stricker (71) Zach Johnson (68) and Gary Woodland (67).
The third round will get underway at 7.30 am local time after thunderstorms were forecast for Saturday.