Welfare made a bright start and Jordan Buckham, Darren Mansaram and Josh Dodd all went close.Â
However, Campion grew into the game and almost broke the deadlock when a teasing cross just evaded Laurence Sorhaindo.
Armthorpe's AdamÂ Stevens pulled off a couple of fine saves in quick succession but the deadlock wasÂ broken on 76 minutes with what proved to be the decisive goal.
Dan Cunningham got clear byÂ latching onto a through pass andÂ coolly steeredÂ the ball beyond Stevens.
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Liam Radford was not far away from an equaliser with a 25-yard effort whichÂ the visitors' goalkeeper did well to push round the post.
Welfare's hopes of getting anything from the game faded when Steve Garner was sent off with seven minutes remaining for a second yellow card.
Mike Carmody's men went downÂ 5-2 to Shirebrook Town last Wednesday.
Maltby MainÂ came away from Worksop Town with a 1-1 draw in the Premier Division.