If you saw the whole movie, Jason, the victim and deathstalker were friends. But then the victim was bribed to betray deathstalker. He didn't fight for his life because he knew he deserved death for his betrayal.
I love that fight scene. I remember seeing it as a kid and having one of my first strong sexual reactions to a lethal fight between 2 men. That lean, smooth loser's body was so hot and ever since seeing that, being in that role has been one of my most erotic fantasies.