Battling Sky Blues are beaten
Coventry City remain in relegation trouble after Saturday's defeat at Watford.
Leon Best had levelled Nathan Ellington's early goal but Tommy Smith won it for the home side.
Elsewhere at the bottom, Southampton defeated leaders Bristol City, Leicester were brushed aside by Sheffield United and Sheffield Wednesday drew 1-1 with Scunthorpe.
Barnsley drop into the bottom three but have a game in hand but have games in hand on the other sides.