



Personally, I have my bets on sonic, normal Difficulty. While game sonic has far superior feats and cosmology against the entire verse, Goku is known to evolve when he faces a far stronger opponent ( jiren, granola, gas, etc ) so he would definitely push sonic to super form and give him a good fight. But either way, I still lean for sonic because he basically does the same thing at evolving against strong opponents ( infinite ), and his super form gives him at least a infinite power gap.
( screenshot from Disney speedstorm )
It wasn't because of gru tanking 4,000 kilotons, it was because he grabbed one of the minions to protect him considering the minions are mostly indestructible.