The Millers arrived at the Rail Ground having been out of action since the beginning of December but looked sharp in all areas from the outset.
Lee Clay should have notched his first goal of the day in the opening minutes but his header was directed well over the bar from close range.
He did though make amends on 26 minutes guiding the ball past keeper Jon Kennedey to put the Millers ahead.
It was Clay Cross who made it two on the stroke of half-time when he scored from possibly the best move of the afternoon from his team.
It was an end to end affair in the second half that saw Retford with opportunities to claw themselves back into the game but the hero of the afternoon proved to be Lee Clay again who completed his second consecutive hat-trick on 80 minutes.
This Saturday the Millers hope to end the year on a high when Doncaster based, Brodsworth Welfare visit Mill Lane. Kick-off 3pm.