This is a terrible mythbusters way to test a hypothesis. What’s the variance and how many samples are needed for say 95% confidence in disproving null hypothesi

This is a terrible mythbusters way to test a hypothesis. What’s the variance and how many samples are needed for say 95% confidence in disproving null hypothesis? WCC is a dozen+ rounds. Even then if you were watching it in the 9th game, it may appear the one player is stronger than the eventual champion.