That entire scene was kind of odd, odd in that I can't get in Algrens head with this one. I don't know what he was trying to do.
Anyway, Algren wasn't even fighting correctly, he just hap hazzardly held it with one hand, no leverage, no power, it's like he was just messing around. When he was surrounded in the forrest he had the long spear/lanz and was fighting with passion, he used two hands and all of his strength. Besides it was a different weapon...the long spear versus the Japanese sword. As others have noted Ujio was their best swordsman.
Anyway, I'm not really sure what that scene was about. Algren knew he couldn't win the contest and had been beaten, I'm not sure why he was getting up over and over just to be beaten. Was he trying to make Ujio kill him (guilt over his past)? What did Ujio take from the encounter, marvel at his determination, that he wouldn't stop no matter what, did he abhor him more? Was Algren trying to prove a point? If so, what? It's a beautiful scene but it is also confusing.