When two future greats or established greats go head to head for divisional supremacy....some super fights come when they are slightly past prime but both are future hall of famers like....DLH-Mayweather, Leonard-Hearns 1(a) 2(b).....some should have been like Mosley-Pacquaio, but took to long where one was considerably far gone than the opponent
Then only these would qualify Louis-Schmeling II ( representative of Nazi vs America) Ali-Frazier FOTC (Joe Frazier recall that battle in Vietnam was stop just that soldiers could watch this fight) Ali-Foreman (People was hoping Ali will finally be stopped) Ali-Holmes (I remember this was even broadcast in the communist China and the Soviet Union)
You need two big names and the fight needs to be theoretically competitive. DLH vs Mayweatehr was a superfight, becasue they were two big names, and before the fight happened, there was a reasonable assumption that either guy could win. Conversely, a fight like Mayweather vs Mosley was not much of a superfight, becasue althought there were two big names, the consensus was that Mosley had little chance of winning.
Tyson vs. Douglas was supposed to be a routine title defense against an ordinary fighter. It was a super UPSET, but not the kind of fight fans lose sleep over.