The problem with this fight was they were what, 80lbs? there are numerous striking methods that would literally decimate someone with one hit, one of the most simple is a 45/ degree anle hit to the tip of the mandible at full force, this will dislocate your jaw and knock you the fuck out, when you manage to come to you will have the wonderful taste of blood dripping down your throat and be in extreme pain.(and I hear sucking food through a tube is no fun)
Also, a suto at full force to the side of your kneck where your corotid artery is, will cause hemmoraging and probably death. BJJ is a good method for incorporating into others like Da zhimmenge, guazo gonji, and san soo kung fu, but I would not use it exclusively as a self defense method.