Assuming there was some strange situation that brought the two together in straight up one on one combat?
Situation dependent, according to combat mindset (not weapons or basic style) and who's having a better day. Ninja A beats Knight B, but Knight B beats Ninja C, but Ninja C can beat Knight D.....
And the same for the SAS against the SEALS, or Vasili Zaitzev against Carlos Hathcock, or a Kenpo blackbelt against a boxer.
Nuff said?
