It won't get any easier the rest of the way.
Tiger Woods was one shot behind. So was Rory McIlroy. Going into a storm-filled weekend at Crooked Stick, four players who have reached No. 1 in the world were among the top six.
"I've got to keep it going," Singh said. "I've been playing well for two days for a while now, but I need four days of good playing. Sooner or later, I think four days is going to happen. And hopefully, it starts this week."
Woods started slowly and finished strong, with birdies on his last two holes for a 67. McIlroy, coming off what he called one of the best ball-striking rounds of his life, had to overcome four bogeys for a hard-earned 68. Joining them one shot out of the lead was Ryan Moore, who had a 66 and seems to play well in the BMW Championship no matter which state it is held.
Lee Westwood (65) and Indiana native Bo Van Pelt (69) were two shots off the lead.
Canadian golfer Graham DeLaet, who entered the day in a four-way tie for the lead, finished with a 2-under 70 to drop three strokes back of Singh.
The Weyburn, Sask., native birdied holes nine and 14 to fall into a seventh-place tie with South Korea's Seung-Yul Noh.
DeLaet is ranked No. 60 in the FedEx Cup and facing elimination — only the top 30 go to East Lake for the Tour Championship.
David Hearn of Brantford, Ont., hit a 70 and is eight back at 5 under.
Singh was at 13-under 131 on Crooked Stick, a Pete Dye course that is vulnerable to low scoring because of rain over the last several days. The second round was played early Friday to beat approaching thunderstorms, and the times were pushed back slightly Saturday to recover from whatever rain falls overnight.
These are supposed to be the FedEx Cup playoffs. The scores make it look like the old Bob Hope Classic, especially after a week in which McIlroy won on the TPC Boston at 20-under 264.
"You come to a Pete Dye golf course, and you don't expect to see 13-under par leading after two days," Woods said.
He was happy just to be in the mix. For the second straight day, Woods wasn't particularly sharp in any area of his game except for posting a score.
"I didn't have it with my swing," Woods said. "Just kind of fighting it around here. You look up at the scores, the guys are just running off. I just wanted to get to double digits (under par) today. I felt like that would have been a good accomplishment the way I was hitting the golf ball, and happy to get a couple of more."
McIlroy's mistakes all seemed to cost him, whether it was a three-putt bogey or bad lies when he missed the green. He was helped by a brilliant approach on the par-5 ninth to just inside 5 feet for eagle.
"I put myself in a great position going into the weekend," McIlroy said. "The round wasn't quite as good as it was yesterday. I didn't hit the ball quite as well. But I still managed to get around in 4-under par. I'm very pleased about that. I just need to try and find a little more consistency. It wasn't that bad out there, but just a couple of missed tee shots and a couple of missed iron shots."
McIlroy and Woods are both going for a PGA Tour-leading fourth win of the year.
Singh would settle for just one win at this point. His last victory was the Deutsche Bank Championship in 2008, the year he won the opening two FedEx Cup playoff events and essentially clinched the $10 million bonus. He would not have guessed that would be his last win. Since then, he has coped with nagging injuries and has been regaining his form and his confidence.
He shared the 36-hole lead at the PGA Championship with Woods and Carl Pettersson, but a 74-77 weekend sent him plummeting to a tie for 36th. Two weeks ago, he was one shot behind going into the weekend at Bethpage Black until a 76-75 weekend dropped him into a tie for 46th. The big Fijian had a good weekend in Boston, but that only covered up a poor start.
As for what's keeping him from four solid days, Singh isn't sure.
"I have no idea," he said. "I guess I want it so bad that I get in my own way. So I just have to get out of my own way and just play. Last weekend I played better, but I didn't play well the first two days. Hopefully, I can go out there and just shoot two comfortable rounds this week."
A comfortable round might not be enough.
The pins were a little tougher for the second round, but that's not nearly enough to stop the best players in the world who can lift, clean and place their golf balls in the short grass before going after flags on rain-softened greens that putt smoothly because of only 70 players in the field.
It's the perfect recipe for low scoring on any golf course, and that's been the case over two days at Crooked Stick.
The average score over two days have been 69.6. Anyone not at 69 or better was losing ground. There already have been 21 eagles and 621 birdies over two days, which at least gives the sold-out gallery something to cheer.
Bill Haas had the best round Friday at 64, despite a bogey on the 17th hole. There were 32 rounds in the 60s, and only 10 players failed to shoot par or better. That included three U.S. Ryder Cup players — Matt Kuchar, Webb Simpson and Steve Stricker, who had a 73 despite a hole-in-one with a 6-iron on the sixth hole.
Hunter Mahan, concerned about an "empty feeling" after not being selected for the Ryder Cup, had a 73.
Moore tied for 16th a year ago in the BMW Championship and finished third in 2010, both times at Cog Hill. He is at No. 35 in the FedEx Cup, needing to get into the top 30 to advance to the Tour Championship in two weeks for a shot at the $10 million bonus.
Haas is at No. 28, and helped himself immensely with a 64. Haas won the FedEx Cup last year, saving par out of the water during a playoff, but a strange piece of history is working against him. No FedEx Cup champion has ever made it back to East Lake for the Tour Championship the following year.
Much like Singh, however, Haas a lot of work left. Given the low scoring — and there's nothing to indicate that will change — the final two rounds of the BMW Championship would be wide open. Twenty players were within five shots of the lead, a group that includes Graeme McDowell, Dustin Johnson and Phil Mickelson.
"Let's be honest," McDowell said. "You've got to keep going low this weekend."