World No. 1 Rory McIlroy fired his second straight 6-under 65 on Saturday to grab a 1-shot lead after two rounds of the Deutsche Bank Championship.
The PGA Champion finished 36 holes at 12-under-par 130 at the TPC Boston.
Louis Oosthuizen also had a 65 to move into second place at minus-11.
Tiger Woods, the 2006 winner, and Ryan Moore both carded 68s on Saturday. They share third place at 10-under-par 132.
First-round leader Seung-Yul Noh managed an even-par 71 to slip into a tie for fifth at minus-9. He stands alongside Jason Dufner (66), D.A. Points (65), 2011 Masters champion Charl Schwartzel (65) and Chris Kirk (70).
Woods got off to a quick start with birdies at one and two. His tee shot at the par-3 third found sand and he failed to get up and down for par.
After a pair of pars, Woods rolled in a 4-footer for birdie at the sixth. He gave that shot back at the 11th, where he 3-putted from 55 feet out.
Woods ran home a 30-foot birdie effort at the 14th. At the 17th, he converted a 17-foot birdie try to get to 10-under. He parred the par-5 18th after finding rough off the tee, then coming up short with his third shot.
Woods' round could have been much lower, but he missed six birdie putts from inside 18 feet.
"I didn't make anything today. I hit it pretty good, but made nothing," Woods said in a televised interview. "Well, I was two shots back going into today, so I'm kind of right there. There are a bunch of guys stacked up so we have to go out there and make some birdies."
McIlroy played the back nine first on Saturday. He converted a 9-foot birdie putt at the 12th, then stuffed his second shot within a foot at the 14th.
He came right back with a birdie from just inside five feet at the 15th to move to 9-under. At the par-5 18th, McIlroy drained an 11-footer for eagle to jump to minus-11.
McIlroy, who also won The Honda Classic this year, poured in an 18-foot putt for birdie at the first.
The 2011 U.S. Open champion splashed his second shot into the water on the par-5 second and that led to a bogey. McIlroy also bogeyed the third after missing the green with his tee shot.
McIlroy fought back with a 4-foot birdie putt at the fourth. He made it two in a row as his 9-footer at the fifth found the bottom of the cup. McIlroy parred the final four holes to end at 12-under.
"Very pleased with how I played today, how I played yesterday, as well, and in a great position going into the weekend. I got off to a nice start and sort of just kept the momentum going," McIlroy said. "So yeah, everything seemed to work pretty well out there. I felt like I drove the ball a bit better today and hit more fairways, which gave me some more opportunities to make birdies, and I was putting well enough to take a few of those."
Oosthuizen also played the back nine first and got off to a fast start. He birdied 10 and 11, both from inside seven feet. At the 12th, Oosthuizen nearly holed his second shot as it stopped within a foot of the cup.
He kicked that in to move to 8-under. Oosthuizen came up short with his second shot at the 13th and that led to a bogey. He erased that mistake with a 17- foot birdie putt at 16.
The 2010 British Open winner tapped in a 2-footer at the second. Oosthuizen nearly drove the short par-4 fourth, before he chipped in for eagle to jump into second place at 11-under. He ended there after closing his round with five pars in a row.
NOTES: McIlroy owns at least a piece of the 36-hole lead for the fourth time in his PGA Tour career. He has won one of the previous three times he was in this position...Sean O'Hair eagled his final hole to make the cut on the number at 2-over-par 144...O'Hair will have a chance to advance in the FedExCup Playoffs unlike Ricky Barnes, Rory Sabbatini, K.J. Choi and Charles Howell III, who all missed the cut and will not finish in the top 70 on the points list to move on to next week's event.