Hmm, this is a tough one to set up.
Hmm, I'll take the lazy way out. They're pissed at eachother, for lord knows what reason. They're fighting in a city neither of them are familiar with, for the sake of it, we say Chicago.
Neither the X Men nor the Fantastic Four are able to interfere in this contest. Pryo has his blowtorches, but I somehow doubt it will do him any good. Human Torch is Human Torch, and both are 100% peak physical condition going into the fight.