A highly encouraging video, of a native wallaby species chasing away a red fox, introduced from Europe. The species is likely a red wallaby.
It is quite simply a fact, that in many places, while introduced predators have an easy time predating young, often adult wildlife can either escape or fight back. This is true in this situation, and adult Kiwi birds are capable of fighting back in New Zealand.
Never-the-less it is quite simply an issue, that we have transferred species all over the world. While this is a greater threat on smaller islands (places like New Zealand – this island was full of various flightless birds, but having introduced land predators, many of these species are either on the verge of extinction, or are only doing well as a result of work by humans.