He still had a four-shot lead.
He was one round from capturing two trophies worth $11.44 million, including the FedEx Cup.
The Swede just made the final day of the PGA Tour season a little more interesting over the last two hours of a dreary Saturday morning at East Lake. He had a nine-shot lead at the turn and walked off the 18th green with a three-putt bogey and his lead back to where it was at the start of the day.
''Of course, I want to win two,'' Stenson said after a 1-under 69. ''If I can't win two, I'll be very pleased to win one. If I'm winning nothing, it will probably be not so sweet from this position. But I didn't have anything when I came here, so we'll see what we'll leave with.''
Stenson appeared to have both wrapped up when he got up-and-down from a bunker on the par-5 ninth for a tap-in birdie to reach 14 under, nine shots clear of Dustin Johnson. Everything changed as the rain began to fall.
Stenson made four bogeys on the back nine, it might have been worse if not for a pair of 12-foot putts he made on the 14th hole for bogey and the 17th hole for par. Johnson was five shots better on the back for a 67, matching the low round of a tough day for scoring and got into the last group.
''I think I'll choose to look at it from the bright side, even though the weather is not that bright at the moment,'' said Stenson, who was at 11-under 199. ''Started the day with a four-shot lead and I still got it. So that's all that matters really.''
Johnson and Steve Stricker, who had a 68 and was at 5-under 205, were the only players within six shots of him.
Johnson was the last man into the 30-man field at East Lake, and he left Chicago on Monday not sure whether he would get in. Now he at least has a shot to start and end the season with a victory. Johnson's other win this year was at Kapalua in the Tournament of Champions.
''If I keep driving it straight, then I'm going to give him a run tomorrow.''
Stenson, the No. 2 seed in the FedEx Cup, is still in great shape to go home with a lot of money – $10 million for winning the FedEx Cup, $1.44 million for winning the Tour Championship. Even if he were to finish third, he still would be in good shape to win golf's biggest payoff.
Tiger Woods, the No. 1 seed, didn't make a birdie until he chipped in on the 14th hole. He rallied for a 69, the first time he has broken par all week. Woods was at 3-over 213, 14 shots behind in a tie for 26th.
Among the other FedEx Cup possibilities Sunday:
-Stricker, who had a 68, could win the FedEx Cup by winning the Tour Championship. He could win with a runner-up finish, provided Stenson finished lower than ninth and Zach Johnson - in the group at 4-under 206 – was worse than seventh.
-Zach Johnson, the No. 4 seed, still had a shot at the $10 million even without winning. He was seven shots behind, but one scenario is for him to finish runner-up and Stenson to finish third.
- Yes, even Dustin Johnson is mathematically still alive as the No. 30 seed. He would need to win (possible), have Woods finish last (possible) and make sure Stenson finishes in the 15th place (total long shot). Johnson wasn't interested in all that math and it wasn't his field of study at Coastal Carolina, anyway.
''They didn't require math,'' he said.
All he cares about are the scores, and he's still in with a chance after making up five shots on the back nine. That was mostly Stenson's doing. The Swede got loose with a few shots, and the rain didn't help.
''I can't really complain that it was any tougher for me than for anybody else,'' Stenson said. ''When you lose a little bit of momentum ... it's just hard to find your rhythm again when you're kind of jumping in and out from underneath an umbrella and trying to whack it to get back in underneath again. So it's a little more difficult, but we still kept it together. Like I said, we've still got a four-shot lead.''
If anything, he felt bad for Adam Scott, whom he led by four shots at the start of the day.
Scott felt so miserable overnight and Saturday morning that he had IV fluids administered at East Lake and showed up on the range only about 25 minutes before his tee time. He was sick and it showed with a 40 on the front nine. Scott wound up with a 74 to fall nine shots behind and was thankful to doctors for getting him ready to play.
''Pretty disappointed, because I felt like I could have made a run today,'' Scott said. ''When your body is feeling so lethargic and heavy, the club feels like it weighs 60 pounds. And it was just hard work to get anything moving.''
That might have ended his bid for PGA Tour player of the year. A win would have given the Masters champion three wins (including a major) and the FedEx Cup, which might have been enough to trump Woods and his five wins (no majors).
DIVOTS: Stenson was able to find another 4-wood overnight and played with 14 clubs. ''I didn't use it once,'' he said. ... Jordan Spieth, playing in the final group with Stenson and Scott, shot a 71 and was in the group seven shots behind with Justin Rose and Billy Horschel. ... Phil Mickelson shot 70 and was nine shots out of the lead.