Since this is a fantasy fight, some rules have to be established. I think that is why the idea of a boxing ring has been mooted.
To allow each fighter to use all their abilities make it an MMA/UFC type match. Each combatant is at their peak, there are no rounds, no scoring, just fight till someone gets KO'd or submits. Kicks, punches, grapples and holds are permitted. No biting.
Ok given the conditions i set above; who would win?