How to determine winrate?

Question

Algorithms

team A vs. C win rate = 80%
team B vs. C win rate = 65%
how to find out the win rate of team A vs. B
thanks

Answer 1

No way. Perhaps the results of B against C are worse because B was preparing to play against A. And A - on the contrary, to play against C. Then it may turn out that A will always lose to B. And it may be the other way around - when A knows B's weak point , which C does not know. Then A will win, perhaps even more often than 80% of the time.
To be able to say something, we need a model - if possible, one-parameter.

Answer 2

Let A play N games against B)