Cups, nice.
I don't like pure randomness. If it is going to be a cup, with one and only one winner then fine, after all in that case it doesn't matter who reached the final, it only matters who won it.
But if you are going to give "silver" and "bronze" medals then pure randomness sucks because there is a high chance you will get a result like:
gold->pro
silver->newb
bronze->pro
It's simple: knock-out systems just suck at ranking people, skilled players end up knocking out other skilled players in one branch while the other branch is full of %&!#@ players.