The other guy is just as scared as you are.
He may be your enemy. He may be your ally. You may have one of each—or thousands. Whomever the other guy may be, remember that you're both terrified to face the fight.
Stand your ground. Don't fear the enemy as much as he wants you to. If he is overconfident then he's more likely to lose. Your allies need you just the same. Be there for them. Be reliable. Be dependable. Be where you need to be in order to help your friends. Don't move; stay where you'll win.