Well, if it was found in a regular garden, then it's probably not a space alien or monster from the depths of hell, so the "strange creature" may not be very correct, strange implying something unknown...
I'm saying opossum as well. The picture makes it look like a quite large animal, but that's probably just an optical illusion. But anatomy makes me doubt very much it would be a coati.
That said, I would not initially think "just a regular animal" if I saw that thing in my back garden. It looks relatively creepy with the hairlessness and almost human-like position.