We have a big dog ~160# Cane Corso, neighbor had a small Heeler of some sort. The heeler would come to our yard and try to fight , our dog would put up with it for a while then bulldozer the little yipper and send it packing.
One day the little yipper thought he was big and wouldn't leave/ kept growling and biting our dog, well ours finally got fed up, and crunch crunch, heeler was no more.

Dogs rarely kill another dog, if, the loser gives up and acknowledges the "leader of the pack".