ATLANTA, 25 Sept 2015, (AFP) - Stenson, owner of a two-stroke lead after his first-round 63, was pleased with his effort on a rain-soaked East Lake course that yielded few low scores.
His nine-under-par total of 131 put him three clear of Masters and US Open champion Spieth, whose bogey-free four-under 66 was the round of the day and put him at six-under 134 through 36 holes of the US PGA Tour finale.
"I didn't feel like it was my best day, but I managed to keep it together and two-under around here is never bad," said Stenson, adding that the drizzly weather made for tough playing conditions.
The average score on Friday was 71.6 and the second round produced just four rounds under par.
"Today was a difficult day, it was a difficult golf course for sure," Stenson said. "It played much, much longer ... I saw Jordan shot 66 -- which was a great round."
After a steady seven pars to open his round, Spieth warmed up with back-to-back birdies at the eighth and ninth.
After a birdie at the par-five 15th, the 22-year-old American capped his round with a birdie at the par-three 18th -- where he drained a 20-footer.
But Spieth said it was a handful of par saves that really made his round. That included a 17-footer for a par save from a bunker at the par-three sixth, and a gutsy save from the rough at the fifth.
"It was huge," Spieth said, noting that his third shot through a tree at the fifth "wasn't necessarily smart" but was still the best option.
"And I had to have the wind blowing this branch back and forth, I had to hit it when it blew it this way or else it would have gone up into it," he said.
England's Paul Casey was alone in third despite a bogey at the last that gave him a 70 for 135.
British Open champion Zach Johnson completed a roller-coaster of a 70 that included a double-bogey and four bogeys as well as six birdies for 136.
He was one stroke in front of world number two Rory McIlroy (71) and Australian Steven Bowditch (69).
In addition to the $1.48 million tournament winner's prize, players in the elite field are chasing the $10 million bonus on offer to the winner of the FedEx Cup playoff series.
Stenson and Spieth are among the top five players in the standings who are assured of nabbing the bonus with a win -- as are newly minted world number one Jason Day, Rickie Fowler and Bubba Watson.
Day, who supplanted McIlroy atop the world rankings after his victory in the BMW Championship last Sunday, struggled to get anything going.
He had two birdies and three bogeys in a one-over 71 that gave him a share of ninth place on 140.
Stenson, the 2013 playoff champion, is trying to join Tiger Woods as the only players to win the FedEx Cup twice, and he was quietly confident he could keep up his bid for a first title of the season on a course that seems to suit him.
"It sets up well for solid iron play, and I seem to bring that," Stenson said, although he's expecting a stiff test from Spieth, and perhaps others, on the weekend.
"I've got to focus on my game and bring my game and keep my head down and foot down and press on if I want to leave the guys behind me," Stenson said.
Second-round scores on Friday in the $8.25 million US PGA Tour Championship, final event in the FedEx Cup playoff series (USA unless noted, par 70):
131 - Henrik Stenson (SWE) 63-68
134 - Jordan Spieth 68-66
135 - Paul Casey (ENG) 65-70
136 - Zach Johnson 66-70
137 - Steven Bowditch (AUS) 68-69, Rory McIlroy (NIR) 66-71
138 - Justin Rose (ENG) 70-68
139 - Rickie Fowler 69-70
140 - Jason Day (AUS) 69-71, J.B. Holmes 68-72, Brandt Snedeker 68-72
141 - Matt Kuchar 71-70, Bubba Watson 70-71, Dustin Johnson 69-72, Danny Lee (NZL) 69-72, Hideki Matsuyama (JPN) 69-72, Kevin Na 68-73
142 - Daniel Berger 69-73, Brooks Koepka 68-74
143 - Bae Sang-Moon (KOR) 73-70
144 - Jimmy Walker 73-71
145 - Charley Hoffman 73-72, Bill Haas 72-73
146 - Patrick Reed 72-74
147 - Scott Piercy 74-73, Harris English 71-76
150 - Robert Streb 75-75
153 - Kevin Kisner 76-77
WD - Louis Oosthuizen (RSA)
DNS - Jim Furyk