You also need to take into account that the knife guy and bat guy have different game plans. If knife guy can get close enough to bat guy, his bat won't be nearly as effective as a knife, which is effective at close range. Knife guy also only needs one hand to deliver a killing blow, while the bat is pretty much useless unless you're holding it with both hands.

The way I see it, Bat guy is going to try to play to his advantage, and be kind of stand offish. Knife guy is going to be aggressive and try to get as close as possible. If they are both playing the optimal strategy, Knife guy is going to rush in there, while bat guy tries to time his swing right. I see knife guy using his free hand to try and catch the bat before it builds up too much speed. Worst case scenario, he breaks his free arm. But I don't see bat guy getting out of this without being stabbed.

Still not a great scenario for either dude.