Kelly, the 2005 winner, was leading Nissan's return to the race for the first time in 21 years but was left crestfallen after the marsupial found its way onto the Mount Panorama track.
"Skippy jumped out in front," Kelly told reporters. "You can tick every box but there are things that you just can't control at Bathurst.
"This is my 16th crack at it but it is probably the toughest," he added. "Not being able to get behind the wheel is the hardest to take."
The crash caused the first of two yellow flags in the five-hour, 1,000 kilometre event - known in Australia simply as "The Great Race" - which was won for the first time by Ford's Mark "Frosty" Winterbottom after a dramatic finish.