I studied Byzantine history lately. I am familiar with the tradition of champions from opposing armies to duel before battles in the east. What baffled me is that time and again, the Byzantine champions kept losing those duels to Muslim ones.
Why was that the case? One would expect some kind of parity but it did not seem to be the case.
This is my first history question, so sorry if I make mistakes.
According to this MA thesis, the Byzantine armies had a number of overall advantages, but it does not follow that their commanders were especially skilled at one-to-one combat. Forcing individual Byzantine commanders to fight duels was an effective Arab strategy to exploit this weakness. (EDIT: As mentioned by @MarkC.Wallace in the comments, the Mubarizun were an Arab unit that specialized in single combat. It appears that that the Byzantines may have lacked any similar specialization.)
Specifically, at the Battle of Ajnadayn:
it was the Byzantine commanders who had the greater tactical and strategic expertise; thusly al-Walid chose to weaken the Byzantines using their own vanity as a weapon. The Muslims’ individual champions would march out to the fore and challenge the Byzantine officers to single combat. Unfortunately for the Byzantines, this ploy worked. Scores of experienced Byzantine officers were killed by the more martial and battle-tested Muslim officers.
One of the prominent Arab champions who defeated numerous Byzantine officers in that battle and others was Dhirrar Ibn al-Azwa.
