You know, this is probably one of the few times where I saw the "punish the bully" trope was done correctly. Yeah, the teacher is a prideful asshole with a trunk stuck in his *** but he is competent enough to back up his words. He realized he was facing someone whose raw power was much higher than his own, so he used a good strategy, a variety of magic that relied more on intelligence and speed rather than power. He lost simply because he was facing an impossible force but he is clearly a talented mage. If he gets an ego check and becomes a bit more respectful, he could actually be a decent teacher.