Just come back from walking the dogs tonight , abd a large-ish lab x rottie was in the park. It saw Tilly, came running over, tail up, hackles up, growling - flew on Tilly's back and tried to put her on the floor and attack her.
Fourtunately - she wasn't having any of it!!

She turned around, snarled, grabbed the dog's muzzle and after a few seconds struggle, put the dog's head on the ground. I called her and she walked away.
The other dog slouched off with it's tail down. The owner apologized and said "Thank you for teaching my dog a lesson - he's a nightmare"
She then proceeded to let it off the lead to chase a collie pup
Some people will never learn!