Chris Tidland, Steve Allan and Brandt Snedeker share fourth place at 4-under 67 -- one shot ahead of six players who are tied for seventh at The Houstonian.
This event is the last chance for players to move into the top 20 on the Nationwide Tour money list and earn a potentially career-changing invitation to the PGA TOUR next season.
With that in mind, each of the three co-leaders entered this week in a different position. And all three showed up to play Thursday, their 67s setting a scoring record at the Rees Jones design.
Kresge, who won his third title at this year's Oregon Classic, safely ranks fourth on the money list with a guaranteed invitation to the PGA TOUR next year.
Playing in a late group on Thursday, Kresge, a former PGA Tour player, made a 30-foot eagle putt at the par-5 16th to join Christian and Buckle in the lead.
'I knew if I could make it by today I would be okay,' said Kresge, who was playing with an inflamed toe on his right foot. 'I knew my golf game was pretty good. I'm swinging it as good as I have in two or three years.'
Buckle, meanwhile, currently sits 18th on the money list after a solid rookie season that produced a surprising win at the Virginia Beach Open in May, where he finished at a record-setting 20 under par.
An Australian, Buckle made two ugly bogeys early on Thursday. But taking solace in the fact that there is no cut this week, he posted seven birdies after that, including five straight from the ninth.
'If I knew I had to battle to make the cut, things might have been different,' said Buckle. 'I could have been 4 over quite easily. And when I look back I could have shot 65 or 80. This is a strange game.'
Christian, who ranks 58th on the money list, also had seven birdies and two bogeys in his first round -- this after he almost withdrew Tuesday because of painful back spasms.
The Englishman one-putted on each of his final five holes, with three of them producing birdies.
'It was just a wonderful way to finish my round,' he said.
Paul Claxton, Chris Baryla, Kyle Reifers, Tim O'Neal, Brendan Pappas and Boo Weekley are tied for seventh place at 3-under 69. Eight players are knotted one stroke further back in 13th.