Although I believe that any average practicing Yid has enough knowledge to withstand any such encounters, please note that this is not something that anyone should engage in a debate unless you are really versed with your opponents beliefs and ‘proofs’.
One person that was an expert in this, is Harav Avigdor Miller. Harav Miller spoke about these subjects (foreign beliefs) at length.
He debated and studied Christianity.
I once heard a shiur from Harav Miller in which he reviewed a lot of Pesukim from TANACH that the Christians use as proof to their Religion. he explains the real dikduk and the real TEITCH, and exposes how they twisted just one word in order ‘prove’ their religion.