Matteson and Imada (67) had 10-under 134 totals on the Greg Norman-designed TPC Sugarloaf. And both failed to take full advantage of the 18th hole, a par 5 that gave up 20 eagles in the second round.
D.J. Brigman (67) was a stroke back, and first-round leader Kevin Sutherland (71) followed at 8 under. Masters champion Zach Johnson (66) was 7 under along with Camilo Villegas (67) and Craig Kanada (70). Villegas flamboyantly removed his cap and bowed to the gallery after hitting a 5-iron within 6 feet on No. 18 set up an eagle.
Imada birdied the 18th, while Matteson made a par.
'The greens might have been a little softer,' Imada said. 'The pins were in an easier position, though, today. So it was easier.'
Matteson, who became the first Georgia Tech player to win an NCAA individual title five years ago, expects to engage in some trash talk with Imada, the best player on the Georgia team that won the 1999 NCAA team championship.
Even though he attended Georgia Tech after Imada left Georgia, the rivalry between the two schools remains intense.
'You know, obviously we hated one another in school, but we're pretty good friends now,' Matteson said. 'If (Imada) wins or a Tech guy wins, it's always a little bit of bragging rights to take home with you, but it's all in good fun now.'
Johnson, the 2004 tournament winner, gained six shots on the field with his 66.
'I love playing in Georgia,' said Johnson, an Iowa native. 'The people are great here, and things have worked for me OK.'
Matteson, whose lone PGA TOUR victory came last fall in Las Vegas, entered his second event at TPC Sugarloaf having missed two straight cuts and six of 10.
'It's been, you know, a long couple months, but hitting some better shots, hitting some better drives and keeping the ball in the fairway has really helped me,' Matteson said. 'Today it all came together. The putting came together, so it's a little bit of a shock to see a 64 after not working on it that long, but I'll take it for sure.'
Imada, from Japan, kept his composure despite a double bogey on the par-5 fourth. A streak of four straight birdies that moved him to 11 under ended when Imada acted hastily with the next group already on the tee.
With his caddie still walking up the fairway after raking a bunker for Tommy Armour III, Imada walked off his yardage from the wrong sprinkler head and used a sand wedge that came up 22 yards short.
His ball landed in the water.
'It wasn't a bad shot,' Imada said. 'So it wasn't overly disappointing, I guess.'
With a 67 for the second straight day, Imada believes he has moved past a difficult five-tournament stretch that included a withdrawal and three missed cuts. He finished ninth at the Byron Nelson and earned money at Wachovia and THE PLAYERS Championship.
'I'm obviously playing well, so I hate to make mistakes,' Imada said. 'But I know I can recover from it, so it's all right.'
Henrik Stenston, David Toms and Lee Janzen were among those tied for 15th at 5 under. Stewart Cink was tied for 55th. Among those missing the cut at even par were Chris DiMarco and Charles Howell III.
A day after John Daly withdrew because of a shoulder injury, Rich Beem (flu) and Vaughn Taylor (allergies) pulled out of the tournament.