I might be getting into minutiae with this, but I'd expect that (Spidey = underdog versus Scorpion) because in a single issue Spidey should be the on the ropes against him to show he's a threat. It's Spidey's intelligence and access to entangling/restraining webs that gives him a shot at defeating Scorpion through some means other than just raw fisticuffs.
Of course, then you get into the whole thing of how/why does Scorpion have more Strength than Spidey, or why in one comic panel can his armor resist ABC but in another he gets knocked out by XYZ, and...anyway, comics are funny like that sometimes ;-P