I agree with the throat kick or a hard square punch to its nose can render it into a sneezing fit.

If a dog is locked on to another dog/person another way of disabling them is to reach over and grab both its front legs and pull them out sideways from under the dog while putting maximum weight or even your knee as leaverage in the middle of its back. This wont work on real big dog because you wont get the force.
This is a weak area and can break its ribs as well as dislocate its shoulders.
Or if you can flip it over and push its legs out side ways can work to if you can get enough weight into it. I herd of someone doing this to a rotweller that attacked someone when I was a kid. I remember my Dad explaining it to me when I was about 7, and it alway stuck in the back of my mind.
It takes more guts and strength than grabbing its back legs and some people wont be able to manage it, but if there is a child getting mauled it is another option to disable the attacker.
Im a dog lover and hate to see dog injuries, but I wouldnt hesitate if it was my family or friends, and I would seriously think about it if it was my dog getting attacked.