I've always wanted to ask a professional keeper about this sort of shot. The ball comes at clark right beside his left foot and, as you said, he dove short, which is much harder and requires much faster reaction times. I think my instinct would have been to simply kick the ball away wide (to the right in this instance) or to attempt to trap the ball with my foot like a field player and then collapse on it.
My guess is they are taught to dive on a ball and get their hands on it regardless of where the shot is to prevent rebounds as much as possible. But we also see great keepers in europe making kick saves. It benefited us for sure, but if i were clark, i think i would have kicked it away. lol.
THANKS CLARK!