Unaka was unable to keep pace with a quick start on Friday.
The Rangers fell 56-0 to Cosby in Region 1-A play in Cosby.
Cosby returned the opening kick for a touchdown and quickly extended the lead. The Eagles led 42-0 after a quarter of play.
Unaka kept battling, but was unable to get anything going.
The Rangers are set to host Hancock County next Friday.