If Singh finishes better than a tie for sixth on Sunday, he will become the first player in PGA Tour history to eclipse the $10 million mark in single-season earnings. If Singh visits the winner's circle Sunday afternoon, then captures next week's Tour Championship, he would become the fourth player to collect double digit wins in one year.
'I'm not really worried about the 10 wins. I just want to play well until the end of the season,' said Singh, who can join Byron Nelson, Ben Hogan and Sam Snead as the only golfers with 10 or more victories in one calendar year. 'If I win this week, fine, then I have to do it again next week, and next week is a really difficult tournament to do.
'I haven't even won this week, I'm just leading. I just have to focus on what I'm doing, be in the present and stay in the present.'
Armour, who established a PGA Tour record for lowest 72-hole score with a 254 at last year's Texas Open, shot a 3-under 68 on Saturday. Jesper Parnevik and Kirk Triplett both carded 68s in the third round and share third place at 10-under-par 203.
Singh struggled early on Saturday with back-to-back bogeys at two and three, but rebounded with a birdie at four and a 7-foot birdie putt at the fifth.
After an 8-footer for birdie at the seventh, Singh then tapped in a short birdie putt at the par-5 11th to join a logjam in first at 10 under par. He missed the green left with his second shot at the par-5 14th, but chipped to 4 feet to set up birdie and caught Armour in the lead at 11 under par.
At the par-3 17th, Singh hit a 4-iron 25 feet short of the flag. His birdie putt disappeared in the cup and Singh took his sixth 54-hole lead this season. He won the previous five in 2004 and has hoisted the trophy the last 10 times he held at least a piece of the 54-hole lead.
'At a tough golf course like this you don't worry about what the leads are, you just keep pace and keep your patience and see if you can get a chance on Sunday,' said Singh, who overtook Tiger Woods atop the world rankings after his win at the Deutsche Bank Championship. 'Fortunately I've done better than that this year.'
Armour traded a birdie for a bogey at the first and third holes, then ran home a 20-footer for birdie at the sixth. He reached 10 under par with a 15-foot birdie putt at the seventh and never found himself far off the lead from that point.
At the par-5 11th, Armour hit his drive near a tree, then pitched out to the fairway. He knocked his third to 10 feet and holed the putt to take sole possession of first at minus-11.
Singh caught Armour at 14, but Armour failed to record another birdie the rest of the way. He had good looks at birdie at 14 and 15, but missed. Armour got up and down from a greenside bunker at 17 and avoided a potentially serious problem at the closing hole.
His drive found the rough on the left side and his 7-iron second shot hit the grandstand on the left side. Armour's ball bounced off the seats and landed on the fringe. He nearly chipped in, but settled for par.
'I actually was just aiming at the pin, and if it goes a little left I'll hit in the stands and I'll be able to drop it over there and have some kind of chip up at the pin,' said Armour. 'End of the year in the last group with the No. 1 player in the world? Pretty good.'
Two-time Masters champion Jose Maria Olazabal (67) and Tom Carter (65) are both outside the top-125 on the money list and are in danger of losing their PGA Tour cards unless they can post good finishes in this week's final full-field event of the year. The duo is knotted in fifth place at minus-8.
Jeff Sluman, who shared the 36-hole lead, struggled to a 3-over 74 and is tied for seventh place with former PGA Championship winner David Toms (67), Robert Allenby (69), Carl Pettersson (71) and Tim Herron (67). The group is tied at 7-under-par 206.
Herron is 34th on the money list and with a big finish and some help, can break into the top 30 for an invitation to next week's Tour Championship.
Jonathan Byrd, who shared the second-round lead with Sluman, was worse than his fellow co-leader on Saturday. Byrd shot a 4-over 75 and is part of a group tied for 12th at minus-6.