Couch collected his second win of the season after capturing last month's Rheem Classic. This was his fifth win on the Nationwide Tour, which ties him for third on the all-time list.
'I told Pat Bates I was coming after him this year. I knew he was leading and we're good buddies,' said Couch. 'I've been through a lot of ups and downs in my career. This is definitely one of the highs here.'
Kevin Durkin shot a 4-under 67 in the final round and tied for second with Mario Tiziani and Paul Gow, who both shot rounds of 3-under 68. The trio came in at 11-under-par 273.
Couch came into the final round with a two-shot lead and parred his first four holes. He broke into red figures with a 6-foot birdie putt at five and a 3-footer for birdie at six. Couch parred his final three holes on the front nine to take a three-shot lead to the back nine.
At the 10th, Couch hit a sand wedge 15 feet short of the hole. He sank the birdie putt, then parred his next two. Couch ran home a 5-foot birdie putt at the 13th to go four ahead, but when Gow bogeyed back-to-back holes from the 14th, Couch's margin was five.
Couch hit a terrible drive into the left rough at the 14th and was forced to pitch back into the fairway. His third landed on the back fringe and he missed the putt to bogey the hole for the second consecutive round.
Couch hit driver off the tee at the short, par-4 15th and came up just short of the putting surface. Using his cross-handed chipping grip, he pitched the ball inside 2 feet and tapped in for birdie.
That was all it took for Couch.
'I got off to a rough start on the first four holes when I hit it all over the ball park,' said Couch. 'I broke an 8-iron on the third hole. But I think those four holes set the pace for me. I found my swing and hit it good the rest of the way.'
If Couch can visit the winner's circle one more time this year on the Nationwide Tour, he will earn the immediate 'battlefield promotion' to the PGA Tour. Even if that doesn't happen, he has appeared to pocket enough money to already get to the big tour through his place on this year's money list.
'I definitely have some work to do on the PGA Tour,' said Couch, who gets a spot in the Western Open field on the PGA Tour with his win on Sunday. 'I have something to prove.'
Camilo Villegas (65) and Mathew Goggin (68) shared fifth place at 10-under-par 274, while Dicky Pride (66) and Steve LeBrun (70) tied for seventh at minus- 9.
Roger Tambellini (67), Mathias Gronberg (69), Brendon de Jonge (71) and Jon Mills tied for ninth at 8-under-par 276.