Gavin Coles shot a 7-under-par 65 to share second place with Brendan Jones.
'Things like that doesn't just sink in,' Singh said of being chosen for the Hall of Fame. 'It's no big deal at this particular moment. I mean, it's a great feeling to have, but I think weeks and months from now, it's going to be a really big deal for me.'
At the par-4 17th, Singh dropped an 8-iron inside 16 feet and drained the birdie putt to make it three in a row. The former No. 1 player in the world then dropped his approach within a foot of the hole for a tap-in birdie at the par-4 second to move to 5 under.
'It sets up for longer hitters if you're hitting the ball straight,' said Singh. 'I drove the ball pretty straight and pretty long. When you do that, you have a lot of looks at the holes for birdies.'
Singh hit a wedge to 4 feet at the par-4 sixth and converted the short birdie try before his second shot to the par-4 seventh landed within 4 feet of the hole. Singh rolled in the putt for another birdie to move to minus-7.
The 42-year-old closed his round in style at the par-5 ninth and pitched his third shot to a foot for another kick-in birdie.
'You've got to focus on what you're doing,' said Singh, a two-time winner of this event. 'My focus this week is coming out here and playing the Houston Open. This is my real focus.'
Coles ran off back-to-back birdies from the second and drained a 40-footer for a birdie at the par-3 fifth to jump to 3 under. Coles then birdied the sixth and knocked his tee shot inside 10 feet for a birdie at the par-3 eighth.
The Australian tallied a birdie at the ninth and sank a 30-foot putt for a birdie at the 12th. Coles dropped his tee shot within 3 feet for a birdie at the par-3 13th to join Singh at 8 under but he found trouble at the par-4 16th after his second shot landed in a greenside bunker.
Coles was unable to get up and down for his only bogey of the day. He then parred his two remaining holes to finish within one shot of Singh.
'I just kept hitting it on the fairway and hitting it on the green and a few went in,' said Coles. 'Just every time I sort of looked at it, I seemed to read the right line.'
Jones started with a bogey at the 10th, but recovered with three consecutive birdies beginning at the par-3 13th. The Australian then tallied four birdies on the front nine to join Coles in a tie for second.
Jeff Maggert, Jimmy Walker, Tim Herron, Ted Purdy, Chris Smith, Carl Paulson, Greg Owen and Brett Quigley are knotted at 5-under-par 67.
John Daly, Joe Ogilvie, Brian Bateman, Paul Claxton, Tom Byrum and Geoff Ogilvy are one shot further back at 4-under-par 68.