No commander would willingly stake the outcome of a battle on a single combat.
Though possessing a superior force, he was forced to resort to single combat, a sign of a commander's incompetence...
Yet he had truly never encountered such tactics before and, for the moment, could not come up with an effective method to counter it. He saw only two paths before him.
Either he had to personally intervene to intercept Sparrow Bee. His opponent, a master of the same caliber, was extremely fast. Trying to encircle him would simply waste time and effort with no effect, leaving only self-restrain as an option.