If you mean the latest one (I can't remember if they have fought many times during the fillers...), it was in the episode #196. Although it's the second episode of a 2 episodes arc that started with #195..

Hard to say if it's worth downloading just to see that fight. First of all, the fight is very tightly coupled to the plot of the arc, and much of it wouldn't make much sense without seeing the whole thing. Well, you gotta decide that for yourself, of course.