Kresge was joined atop the leaderboard at Royal Adelaide Golf Club by Australian Steven Bowditch. A pair of Australians - Craig Jones and Greg Chalmers - share third place at 4-under-par 68.
Kresge got off to a hot start on the back nine at Royal Adelaide. The American birdied the par-4 10th and came right back with a birdie at 11.
The two-time winner on the Nationwide Tour tripped to a bogey on 14, but bounced back with an eagle at the par-5 15th. Kresge stumbled to another bogey at the 17th to make the turn at minus-2.
Around the turn, Kresge really caught fire. He dropped in a birdie putt at the first and made it two straight with a birdie at No. 2. Kresge then drained his third consecutive birdie at the third to climb to 5 under.
Kresge tripped to his third and final bogey at the par-4 fourth. He erased the mistake with a birdie on seven and parred his final two holes to share the first-round lead.
'I thought my ball striking was like I wanted it to be, but my putting was great,' Kresge said. 'I started off perfect by making about a 30-foot putt on the first hole.'
Bowditch opened with birdies at two and three. After four straight pars, the 21-year-old drained a birdie try at the eighth to move to minus-3.
The Australian stumbled to a bogey at the 10th, but turned around and birdied the 11th. Bowditch converted another birdie at 13 to move to minus-4.
Bowditch birdied the 15th, but faltered to a bogey at the next. He atoned for that error and moved into a tie for the lead when he birdied the 17th. He parred the last to share first.
'I went out there with a good frame of mind and made some good saves early, all in all it was a good day,' said Bowditch. 'Actually thought the wind to start with made the course a little easier, especially the wind on the front nine.'
Jeff Gove and Keoke Cotner head a group of players at 3-under-par 69. They were joined there by Brian Kortan, Scott Laycock, Brad McIntosh, Dan Olsen, Martin Doyle, Joel Edwards, Peter Fowler, Jeff Freeman and Ryan Armour.
Euan Walters, who earned his first Nationwide Tour win at this event last year, stumbled to an opening round 5-over-par 77.