Nolan Grayson decides to conquer Earth/Mobius in the name of the Viltrum(ite) Empire. Super Sonic must stop him.

Round I) Archie Comics Super Sonic (both pre and post Super Genesis Wave) vs. comic Omni-Man.

Round II) IDW Super Sonic takes on comic Omni-Man.

Round III) Sonic X Super Sonic vs. Omni-Man (since Sonic X, as far as I can tell, has been the only time that Super Sonic has ever OFFICIALLY shown up in any Sonic cartoon).

Bonus: Paramount Super Sonic takes on the source material edition of Omni-Man.