'I felt so comfortable the whole week but today I was fighting it a little bit,' said Delsing. 'I got off to great starts all week but then hit a lull.'
Delsing once again flew out of the gate. He collected four birdies in a row, starting at the second, and two-putted from 65 feet for birdie at the 10th to take command of the tournament.
But Delsing bogeyed the 15th and 16th holes and Painter left himself with a tap-in birdie at 17 to reach 20-under par and tie Delsing for the lead.
Delsing left himself with a five-foot birdie putt at the 17th, but the putt never grazed the hole. Delsing, in the group behind Painter, hit driver at the 440-yard, par-4 closing hole at The Champions Club. He then wedged his approach to six feet and converted the putt to win the championship.
'I was thinking on the last hole that, 'Man this is cool,'' said Delsing, who either led outright or shared the lead after each round in Omaha. 'That six-foot putt looked like a mile to me. I'm just glad I snuck that one in.'
More from Delsing on his win.
Delsing earned his second victory on the Buy.Com Tour after titling at the Fort Smith Classic last season. He earned $90,000 for the win and jumped to 13th on the money list.
'It's nice for this game to give you something back a little bit after all the work,' said Delsing, a 41-year-old from St. Louis. 'It will be neat playing the week after winning.'
Painter gave it all he could with a final-round 64 but in the end, a two-over 74 in Round 1 was too much to overcome.
'Give credit to Jay, he made a great birdie on the last hole,' said Painter. 'He shot six-under the first round and I shot two-over, so if you're eight shots back after the first day you're just too far behind.'
Chip Beck finished alone in third place at 19-under-par 269. The third-place finish was Beck's highest on either the Buy.com Tour or the PGA Tour since a second-place finish at the 1996 Buick Open.
Chris Tidland took fourth at 18-under par, followed by Craig Lile at 17-under par and Lucas Glover, Andrew McLardy and Tommy Biershenk at minus-16.