if you're against another melee, if they want to smack you in the head, they're gonna have to use some sort of resource, whether it's moving to you, or mana. when someone is moving in to auto attack you or cast a spell, they will have a slight orange aura around them (look for this in your next games!) and you can back off accordingly.
also, don't let them get free damage off if possible. make them pay for going up to rough and tumble with ya