This time, they really did follow the rituals of the Xuanmen, quite courteously indeed.
As mentioned before, a duel of mystic arts is not like a sword fight. It involves reading from scrolls, chanting incantations, and setting up circles for the spells, emphasizing both suddenness and secrecy, hence it is usually executed from the shadows with a surprise attack.
However, the nine great Xuanmen are branches of the same tree, and as long as they haven't turned hostile towards each other, they would still hold a semblance of consideration for feelings. They'd often set up a game, guess a number, or wager on something, to avoid escalating to a point of no return with armed confrontation.