Barnsley's three-match winning run came to an end as they were beaten 2-1 at local rivals Chesterfield on Saturday.
The Reds were twice undone by long balls as League One top-scorer Eoin Doyle put the hosts ahead just before the break after Joe Dudgeon's header played him through then made it 2-0 on 57 minutes with a fine finish.
Substitute Keith Treacy's first Barnsley goal halved the deficit with five minutes to play but the hosts held on to win. The Reds have now slipped into the bottom half of the table, seven points off the play-offs and five clear of the relegation zone.
Danny Wilson kept the same side which won 3-2 at home to Colchester United eight days earlier. Conor Hourihane tested home goalkeeper Tommy Lee with a third-minute shot from 25 yard which was turned around the bottom left corner.
Doyle should have put Chesterfield ahead earlier than he did but directed a free header straight at Ross Turnbull before, at the other end, Lewin Nyatanga's headed effort was saved by Lee.
Spireites captain Ian Evatt headed another fine chance over the bar but the hosts soon went 1-0 up. Dudgeon headed a long ball into his own area and Doyle raced onto it before lobbing Turnbull.
Kane Hemmings had a brilliant chance to level six minutes into the second half when he was played clean throughout but he chose to cut back past a defender and the deflected shot went just wide.
Doyle showed his class to put Chesterfield 2-0 up when he was allowed too much space to bring down a long ball on the left side of the box and fire into the bottom right corner from 12 yards out.
Marcello Trotta was brought on after an hour and immediately put Devante Cole through on goal though the shot was deflected wide. From the resultant corner, Sam Winnall's header was cleared off the line by Tendayi Darikwa.
The Reds pulled one back when Dudgeon burst down the left and whipped in a cross which was cut out by a home defender but the ball fell to Winnall who passed to Treacy to tap in from five yards out.
