Agree with Krak, Redbird and Texas. Even without their good stuff, they keep attacking hitters with whatever their pitches are that day. When things go bad, they bear down and focus even harder.
Son's HS team has kid like this...not the best stuff but a bulldog on the mound no matter what sitaution he is thrown into. Bases loaded, no outs hasn't fazed him yet. My son loves catching the kid because the kid is fearless. Does he win every battle...no, but at least it is a battle.