Yes I went there.

So, who would win in straight-up sword to face combat? No horses, no ranged weapons.
This seems to be another of those x versus y situations that always crops up somewhere, but I haven't seen one here. It really does seem rather silly though once you think about it, because the two would have never fought. A knight's equipment was created for fighting other knights, and samurai were supposed to fight other samurai.
This kind of comparison in no way means one is "better" than the other.However, if I had to pick one, It would be the knight. As far as I know, the samurai's katana is not designed to cause blunt trauma (like a mace or flail), nor is it capable of slicing through the plate armor knights wore. That pretty much seals it right there, the samurai has almost no way to injure the knight.
I might be misinformed about some of this though, so correct me if I'm wrong. Or correct others who are wrong.