He was supposedly reduced to a normal Sakaarian by Doc Green several months ago, but I'm not sure if the serum worked on him. It would not work on Doc Green because of his physiology. Skaar is his son so this is why I'm not too sure if it worked on him either. I'm also not sure if there was a foreshadowing presented at the end either, because the last time Skaar was on panel, there was a distinct green hue in his eyes like he faked being reduced to Sakaarian stats. Anyway, Skaar probably wins this after a good fight.
Wonderman wins seeing as though Skaar currently has no Hulk form. Full powered Skaar should win though, Simon has had like 1 great feat in the last 10 years.