Bar arm the guy till you dislocate his shoulder or dislocate the knee. Two moves easily accomplished if you know a bit of wrestling. I haven't seen too many guys with much fight left following said conditions.
Many wrestlers did not know submission moves until they learned juijitsu. Then they became really dangerous!
My opinion is that it is good to know ground fighting, but fights, but almost all fights start standing up and not all should go to the ground if there are other people around.