Quote Originally Posted by JaySee
No one said the poison affects his mind and he was more than lucid enough to block Sasori's finishing attack, AND take a swipe at him, AND grab a piece of his face mask, AND tell that it was Sasori that poisoned him. His mind seems A-OK.
He lost his consciousness. According to my experience consciousness and mind are somewhat connected to each other. You might disagree, of course.

He could have fought like he did even with a mind starting to be affected due to his heavy training. The fight honestly wasn't so intensive to begin with, and it never looked like he - or Sasori - fought 100%.