INDIANAPOLIS, Indiana, Sept 7, 2012 (AFP) - "I've got to keep it going," the three-time major champion 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."
The Fijian reached 13-under 131 and is one shot ahead of 14-time major winner Tiger Woods and world number one Rory McIlroy who shot 67 and 68. Ryan Moore shot a six-under 66 and is tied with Woods and McIlroy at the Crooked Stick golf course.
Woods, who is chasing his fourth win of the season, birdied three of his last four holes, while first-round co-leader McIlroy overcame four bogeys for a 68.
The top 30 on the FedEx Cup points standings after this event move onto the Tour Championship in two weeks. Singh is currently 49th.
After starting his round on the back nine, Singh got to 10-under par with the help of a four-foot birdie at the 18th.
That started a superb stretch for Singh as he drained a pair of three-foot putts for birdie at one and two, then rolled in a 15-footer for his fourth straight birdie.
"That kind of got me going," Singh said of his birdie streak.
Rory McIlroy, who is coming off a victory at last week's Deutsche Bank Championship, birdied the last hole.
"It wasn't as good a day as yesterday," said McIlroy. "I didn't hit the ball quite as well, but scored well and did enough to go out there and shoot another good number and set myself up in a good position going into the weekend."
Woods, who played in the same group with McIlroy in the first two rounds, also made birdie on 18.
"Today was a struggle," said Woods. "I fought hard to shoot a number today, and the way I was hitting it, I figured if I could get to double digits under par it would be a good accomplishment. I got a couple more out of it."
Lee Westwood had a seven-under 65 and is tied for fifth with American Bo Van Pelt, who had a three-under 69 in round two. They are tied at 11-under par.
Canadian Graham DeLaet had a two-under 70 and is tied for seventh at minus-10 with South Korea's Seung-Yul Noh, who shot a six-under 66.
Reigning FedEx Cup champion Bill Haas fired an eight-under 64 Friday and moved into a share of ninth with Graeme McDowell (67), Dustin Johnson (67) and Padraig Harrington (65). The group is at nine-under 135.
US Open champion Webb Simpson struggled to a three-over 75.
Leading second-round scores here on Friday from the $8 million BMW Championship (USA unless noted, par-72):
131 - Vijay Singh (FIJ) 65-66
132 - Rory McIlroy (NIR) 64-68, Ryan Moore 66-66, Tiger Woods 65-67
133 - Bo Van Pelt 64-69, Lee Westwood (ENG) 68-65
134 - Graham DeLaet (CAN) 64-70, Seung-yul Noh (KOR) 68-66
135 - Bill Haas 71-64, Padraig Harrington (IRL) 70-65, Dustin Johnson 68-67, Graeme McDowell (NIR) 68-67
136 - Robert Garrigus 67-69, Tom Gillis 69-67, John Huh 70-66--136, Zach Johnson 67-69, Chris Kirk 68-68, Troy Matteson 70-66, Phil Mickelson 69-67, Ian Poulter (ENG) 68-68, Adam Scott (AUS) 68-68
137 - Rickie Fowler 67-70, Martin Laird (SCO) 69-68, Louis Oosthuizen (RSA) 68-69, Justin Rose (ENG) 67-70, Charl Schwartzel (RSA) 69-68, Brendon de Jonge (ZIM) 71-66--137