Anything can beat anything, if the player is better enough.

Note that even this doesn't mean "will beat every time."

If I saw the transmuter/ranger fight you described, I'd say to myself: This ranger player is terrible, or, this transmuter player is really good, or possibly some combination of the two. If the transmuter actually got the kill without landing a super-neuro, I'd know that either the skill deficit was immense (e.g., your favorite NFL franchise vs. your favorite junior high B-string football team in tackle football) or the ranger made one or most likely several serious mistakes.