When fighting Sabretooth for the second time, at first it is the same as before. Jump behind him and use your special to throw him into the trucks. After a few throws, he will jump behind the flames and start throwing barrels. Punch them back at him. When he is done with that, he will come back out and start jumping around. When he is in the air, a green crosshair will appear on the ground. Run to it and use your special to defeat him.