I think a lot of people are hinging on some pretty flimsy rationale. But then again it's not surprising considering the sources.
Musashi has killed more men in direct combat than Anakin has. He's killed opponents of greater prestige and repute. He's killed a man with an OAR. He's the forefather of two blade wazikashi/katana use, and Anakin is way too overconfidant and used to fighting weaker enemies.
Say what you will about not being able to compare SW fight scenes to real fighting, but the point is you HAVE TO in order to make a judgment. Movie scenes are the bones and blood of the SW canon, the highest level aside from the man himself. If they show Anakin having a particularly easy to penetrate guard (Which he does) chances are a real swordsman used to killing people would dice him up.