Simple example is that almost all things on said city street can still be used. A car can be used as transport for said human, as cover, as a weapon itself if the enemy doesn't have the physical strength to stop a car moving at high speeds. Even a stop sign can be used as cover to help avoid a hit which even a single one can change a match over to a win. Buildings used to hide and evade the enemy, used to cause misdirection to which then a car could be rigged to give the enemy the idea that they are trying to escape, pulling their attention from the building to let the human fashion something from the resources. Hint: Being Resourceful.
I've won in an RP fight where my only weapon was a handgun and a knife, I had no powers and no natural abilities beyond that of a human. My opponent was called a Demon Lord. He was immune to bullets, his flesh could regenerate so stabbing or cutting was generally ineffective. He could cause fire at the snap of his fingers wherever he wanted, could move twice as fast as a well trained human and could lift a truck over his head. I took cover in a building to avoid his sight and fire, caused a distraction by blowing up the engine of a car to buy myself some time, then fashioned a bomb from things I found inside of the building. I lured him into the building and took a hit but escaped and blew the building, causing it to crash down on him, rendering me the victor. This is just an example of when it happened to me and I highly doubt I'll get out of it without being told it's me stroking my ego but there you go.
EDIT: And after reading your previous comment, all I have to say is that if you're saying that skill is absolutely the ONLY thing they have going for them and otherwise they're a out of shape, moronic, generally weak person then that's not even a discussion we're having. As people see in anime or games, the underdog can typically overcome the enemy through some miraculous means. Miraculous wins are very possible in RP without godmodding or planning, since everything that happens is based on a desire for enjoyment. To create a situation where there is absolutely no way at all for an unarmed human to defeat a godly character in RP is just a very bad RP.