This video from the USA says about itself:
15 October 2016
Gray Fox stalks and tries to attack a very large skunk with predictable results! A very closeup view of the business end of a skunk which is quickly turned toward the fox and then a brief standoff ensues which the skunk wins as the fox moves on leaving the skunk to cleanup leftover bird seed. The skunk continues to keep his amazingly large fluffy tail high in the air for awhile ready to spray until the fox leaves the area completely.
It may be that the fox didn’t recognize the skunk until it sprung to attack and then aborted as it realized that it was a skunk – that is why all skunks carry warning coloration. Skunks are notoriously tough characters and will generally not let loose of their devastating chemical arsenal unless it is really needed.