Can a golden retriever fight off a rottweiler?

No. A rottweiler is built like a fighter: thick neck, large head, powerful jaws and a powerful build. A golden retriever is not bred to fight, but rather hunt and retriever water fowl without damaging the feathers. Thus against an attacking rottweiler, no matter if the golden is bigger than the rottweiler or not, it could not fight off nor defeat such a fierce, strong breed of dog.