Actually, I just punted an AI opponent all over the map with my fleet of destroyers packing normal-mounted null space weaponry. I had ECM, stealth armour, size and racial bonuses, and they had put all their RPs into their Psychic Weaponry and Ship Construction projects, which left them sadly lacking in the Combat Sensor department.
It didn't work so well against the guys on their other side though . . . lucky I got those larger hulls when the first opponent surrendered!