Overnight leader Henrik Stenson carded a second round 66 to open up a commanding halfway lead at The Tour Championship in Atlanta.
The 37-year-old ended the day on 10-under par, four strokes in front of Masters champion Adam Scott and five clear of American youngster Jordan Spieth.
World number one Tiger Woods, meanwhile, will go into the final 36 holes at East Lake a whopping 14 shots back.
Stenson had led by one from Scott after an opening round 64 but quickly extended that to five shots after making a blistering start for the second day running.
He birdied the first, second and fourth to race to nine-under while playing partner Scott fell back after negotiating the same stretch in one-over.
The Swede knows that a win here will secure him the first prize of $1.4m (£875,000) and the staggering $10m (£6.24m) bonus for winning the FedEx Cup.
And after banking his big early lead, the world number six refused to let it go thanks to another superb display of ball-striking.
A birdie at the long ninth got him to double digits under par before he carded his only bogey of the day at the par four 10th.
Stenson, the runner-up at this summer's Open Championship, had several good locks at birdie on the back nine before finally sinking a 20 footer on 16 to return to 10-under. Pars at 17 and 18 saw him post a halfway total of 130.
Scott returned a 69 to finish on six-under while Spieth, the youngest man to ever play in the Tour Championship, fired a 67 to move up to solo third.
Along with Stenson and Scott, Woods, Zach Johnson and Matt Kuchar are the other three players who are guaranteed to win the FedEx Cup and the $10m bonus fund if they win the tournament.
Mountain to climb
Johnson, three-under after a 68, still has hope but Kuchar (three-over) and Woods (four-over after a 71) have a mountain to climb
Woods, who went out in the first group of the day after an opening 73 left him 29th of the 30-man field after Thursday's action, repaired the damage with three birdies to the turn to get back to level par.
He then added birdies at 12 and 13 to get to five-under for the day before a disastrous finish saw him drop six shots in the final five holes and spiral all the way back to four-over.
Woods blamed fatigue for his late collapse, which included a seven at the 17th after pulling his tee-shot into water.
"I put everything I had into that start and didn't have much at the end," said Woods, who has five wins in 15 starts on the PGA TOUR this season and entered the week atop the FedExCup standings. "Just ran out of gas.
"My legs were just tired. I didn't rotate through the ball (on 17), and I turned it over. Same thing I did over on 14. It's been just a long, long grind. We play a lot of golf from the British Open on."