Knight would obviously win that. Samurai would be torn apart. There weapons and armor couldnt match the knights design. Samurai armor would be wrecked by the blunt force trauma knight believed in. Samurais sword while superior quality would have no effect being a slashing weapon. Then the european destrier against samurais steeds (if they even had one), they would be bowled over. Finally sure samurai has a bow but it probably wouldnt be effective enough.

My moneys on the knight in plate armor wielding a spiked morningstar.

i almost guarantee they give it to the samurai because he can meditate.