If we're supposed to assume they're in-character...
Round 1: Honestly, in neither round is it probably in-character for Sonic to just reality-warp Goku's head off or something to that effect, he'd probably go for the brute force approach. Combined with his cockiness and Goku's better (I think?) martial arts training, he might actually get himself nuked in close combat and be at a large disadvantage early on. Goku's also got a pretty solid range advantage, so long-range would go to him as well. They've got roughly equal equipment, as well (possible slight edge to Sonic.)
Sonic's main advantages, here, is his time manipulation. To my memory it's not something he can spam non-stop, but when it is used it's devastating and can turn the tide of the fight (i.e. just reverse all of his wounds and provide a full heal, go back and know what Goku is about to do next, etc.) If he can make effective use of that, and stay at mid-range where he'll be at his strongest against Goku, he'll take it. If Goku catches on and sticks to his face/snatches a Chaos Emerald or two from him (is that even in-character?), he'll win instead.
Overall, I find Goku to actually be more cunning in-combat than Sonic: not tremendously so, but enough to better make use of his advantages and win Round 1.
Round 2: Same as before, except now Sonic A: Will probably get KOed in just a couple hits, and B: Those hits are harder to deliver. Basically, who can make better use of their newfound advantages?
I'd argue Sonic. Goku's strong, but he's used to fighting people more on his level in stats overall: Sonic, meanwhile, has speed as his whole deal, what he's spent his entire career mastering. If he's faster (and quite a bit so, at that) than his enemy, it'll likely just be his war of attrition to win. Round 2, likely winner Sonic.
...honestly, them not being bloodlusted makes a big difference. If they were, Sonic would probably just decide he doesn't like fun/honor/what-have-you and reality-warp Goku to death before he can scream "FREEEEEZY-POOPPPP-" Hehe. Smart move on OP's part, I say.