Round-1 goes to the Predator because of the durability decrease Sabretooth has with the know Adamantium. The Predator's Plasma Caster should be able to fry Creed's brain with a head shot or at least cause enough damage to knock Creed unconscious. Predator's are really intelligent and Creed is not that smart, especially if he is blood lusted
Round-2 goes to Creed because of the added durability from the Adamantium, this gives Creed enough of a edge that he could just barrel through Plasma shots till he pinpointed the Predator's location and tears him a new one with his claws. Predators have health packs, but they cannot regenerate limbs.