That dude put his whole body into that knee; bad guy drops like a sack of rocks and goes to sleep.. You can't buy a better ending.

Agree with you on the training, but unless he was fighting by the old Pride rules (meaning there's basically no rules), that was an illegal knee to a downed opponent. Even Mario Yamasaki would have taken a point.

In this case, however, it was definitely the best weapon for the job.