After a two-week stint in Australia and New Zealand last month, the Buy.Com Tour reconvened its 2002 campaign at Le Triomphe Golf and Country Club.
Thatcher, who missed the cut at the two events Down Under, played the back nine first and got off to a fast start with back-to-back birdies from the 10th. He added another three holes later at the 14th and ran home his fourth birdie of the inward nine at No. 18 to make the turn in 32.
The rookie picked up where he left off with a birdie at the first. At the par-4 fourth, Thatcher climbed to 6-under with a birdie and made it two in a row with another at the fifth.
Thatcher reached minus-eight with a birdie at the seventh and closed out a flawless round with his ninth birdie of the day at the last.
Thatcher, who turned 25 Thursday, came within three shots of earning his PGA Tour card at last year's Qualifying Tournament. He needed a par at the final hole but his approach shot hit a cart path and sent his ball onto the roof of the Bear Lakes Clubhouse.
The Auburn University grad, who won the second stage of Q-School, took an unplayable lie and finished with a triple-bogey seven to tie for 47th at December's Q-School finals.
Perry Moss, a Buy.Com Tour veteran, took the lead at 9-under with two front-nine eagles and five birdies. However, the 32-year-old bogeyed the 16th and 17th to finish at minus-seven.
He was joined by Charles Raulerson, Steve Alker, Craig Bowden and Bruce Vaughan in a tie for second.
Rob McKelvey, who captured this event in 2000, had seven birdies and one bogey to finish three off the lead at 6-under 66. He was joined by Chris Couch, Mike Heinen, Mark Hensby, John Kernohan, Tjaart van der Walt, Andy Sanders and Gene Sauers.
Full field scores from the Louisiana Open