Wow, this is an interesting poll and thread.
I believe he could have done it. There are similar 'mind over matter' stories in the lives of various Saints.
And there's nothing to say that only Judo-Christian belief systems support amazing feats.
The lesson I learn is to determine the intention of your attacker--know your enemy! If he or she comes at you with the intention to do you great harm or kill you, you're presented with a different situation than on in which your attacker comes at you with a more sporting intent--even if the sport is a better-trained athlete bent on hitting the mark.
Of course, I see Jun's point. Who would want to be know throughout history as the one who killed O Sensei?