Better get some rabies shots man, a coon doesn't attack a dog in the open with an avenue of retreat ,I have coons all around my house ,they come in to eat the dogs food if too much is left out.
We had a coon trapped in our attic, it scaled the cedar siding of the house and tore the soffiting loose to escape our dogs ,got it out by putting a ladder up for it to come down.
Those MF's are like a chain saw with a tail can't imagine that guy got out of that double confrontation unscathed.