What can I do if someone else’s dog comes into my yard and tried to attack my dog (on a leash)?

Hello, and I was sitting outside with my family while my dog was on the leash. My dog is a 9 month old, Blue, American Bull Terrier. The people down the street have a similar type of dog, but he’s older. They let their dog out and he ran straight towards our yard and I had to physically pick my dog up and put him in the house before things progressed. I have witnesses of what happened. The dogs owner is attempting to say that my dog is the aggressive one and that my dog had ill intentions. Our landlord persistently tells everyone that the dog isn’t there; even though he’s physically been around the dog. What should I do to prevent anything from becoming worse?