While Tiger Woods climbed into contention and Phil Mickelson fell further behind, Singh took a two-shot lead at the Western Open with a 3-under 68 on Saturday.
The difference, Singh said, is a new driver.
'In the last six months, every week was a new driver for me,' he said. 'So that tells you that I've been searching.'
Singh broke free of a logjam and took the lead at 10 under with a 10-foot birdie putt at the par-4 13th. He shared the lead for a spell with Trevor Immelman, but Immelman dropped back when he bogeyed the par-4 17th from a bunker.
With an opportunity to pull two ahead, Singh did just that, spinning his approach at 17 to within 6 feet to set up his fourth birdie of the round.
Singh will be seeking his 52nd worldwide victory and 30th title on the PGA TOUR on Sunday. He has won 17-of-25 times when holding at least a share of the 54-hole lead, but 19 players are within five shots.
'[I] just have to stay ahead of everybody else, I guess,' Singh said. 'I've got to go out there and play my game.'
One of the players sitting close is three-time champion Woods, who shot a 5-under 66 to climb into a tie for seventh place at 8-under-par 205.
Defending champion Jim Furyk is also three shots back after a 69.
Woods -- competing for the second time since the Masters and three weeks after missing the U.S. Open cut -- has played better each day at Cog Hill, opening with a 72 on Thursday and following that with a 67 on Friday.
'It's nice to actually make some putts and piece together something out there because obviously my last tournament I didn't do that, and then the tournament before that has been a while,' he said.
Woods carded five birdies and an eagle in his third round. Two bogeys also marked his scorecard, but Woods followed the first with his eagle at the par-5 11th and the other with two straight birdies at 15 and 16.
His turnaround since Thursday came with a lot of hours practicing on the range.
'I knew what I was doing wrong, but I couldn't stop it, and in order to stop it you've got to log in the reps,' Woods said.
'You've got to put in the hours. It's just a matter of doing the reps properly and enough times where it gets more engrained and you feel comfortable, and hence I can carry forth with it the next day.'
Sweden's Carl Pettersson, who won the Memorial this season, fired a 6-under 65 and leads a group of five players who are tied for second place at 9-under-par 204.
As the first player in the clubhouse at 9 under, Pettersson will play with Singh in the final pairing Sunday.
'Tomorrow if I'm in contention, I won't really look (at the leaderboard) on the front nine, but I might have a peek on the back nine,' Pettersson said.
Tied with Pettersson at minus-9 are Mathew Goggin, who fired a 66, and Stewart Cink, Joe Ogilvie and Immelman, who all shot 69.
Mickelson, playing for the first time since his 72nd hole double-bogey at the U.S. Open, fell into a tie for 75th place after shooting a 75. He opened with a 67 Thursday, then shot a 74 Friday and is on pace for his worst finish since missing the cut at the Michelin Championship last October.
Furyk, who held off Woods for the win last year, was one of many players who were tied for the lead on the back nine. After hitting a perfect drive at 18, he stuck his approach on the bank of the greenside lake and finished with a bogey.
'The bright side is I'm a couple back...and in striking distance,' Furyk said.
Overnight leader Daniel Chopra stumbled to a 5-over 76 and fell into a tie for 21st place at minus-5.