While this story is very interesting I don't think it was the origin of Supercross. I still think Mike Goodwin is the creator of Supercross. I'm sure there were a lot of Stadium MX events and MX under lights before The Superbowl of Moto-cross in 1972. Even now not every meeting run in a stadium under lights is called Supercross.
Similarly in my opinion the first Supercross run in Australia was, the "Stefans Superbowl of Motocross" promoted by Blair Sheppard at Archerfield Speedway in 1979. Blair brought two American riders over, Mike Bell and Rex Staten. The track was to a full USA design and it was our introduction to Supercross. Blair ran some fantastic meetings in the three years he ran, at venues like Sydney Showgrounds, Lang Park (Brisbane) and even one in London.
