What works in chess does not necessarily generalize to swordfights. In a duel your responses to your opponent's techniques are mostly cached actions carried out on reflex, and and any ideas you might have about how many times your opponent is likely to try any particular move are not likely to have that much influence on how you react.

How you set up the move certainly makes a difference, the same technique can be used in many different ways, but if you take a specific approach and your opponent defeats it once, you shouldn't count on it working the next time, and if they defeat it twice, you should be even more confident it won't work if you try it again.

From my experience as a fencer, I can affirm that facing a beginner can be disorienting, because when you train to respond to intelligent and efficient techniques, unintelligent and inefficient ones are just confusing. I've never known an experienced fencer to lose to a newbie, because when one person is using efficient techniques and the other isn't, and both are unfamiliar with how to respond to their opponent, the efficient one will win, but it can be pretty frustrating.

On the other hand, having a newbie opponent try the same thing repeatedly even when it's not working is one of the least troublesome things they're likely to do.