Sakuraba or Yoshida.
Saku because of the slams he took from Rampage going for submissions, yet he never quit trying to lock them in(his back had to be hurting). Yoshida because of his fight with Crocop, I was begging for him to stay down a couple times, but he kept getting up and taking another leg kick until he couldn't even stand any longer.
"When I lose, I get my butt kicked. When I win, I be doin' the butt kickin..." - Quinton Jackson