[quote=@Vilageidiotx]
I'd bet on knife. Bat requires swinging to be effective. Once knife is through the effective swing radius of bat, the bat is negated.[/quote]

Bat can also poke, at a much longer range. And bash, and choke, 

Knife guy's only chance is to throw it, pray it sticks, and pick up a rock. In the battle between blood loss and blunt-force trauma, blood loss's best case scenario is a tie (in which they're both dead). In order to [i]win[/i], knife needs to strike a rapidly-lethal blow (easiest is to the neck), but to do so he has to get inside the range of bat guy, and bat guy would have to suck by comparison to let that happen.