User blog comment:KALegend./How powerful is Mordred?/@comment-5829707-20121223042128

Mordred is innately more powerful that Morgana. He had control over his powers at a  far younger age than Morgana. Mordred hasn't been able to practice his magic though. He said at the beginning of Season 5 to Merlin that he had to hide his gifts. I think he would have been almost Merlin's match had he had the opportunities to use his magic the way that Morgana did.