Barnsley dropped out of the play-off places following a disappointing defeat against promotion rivals Southend United.
The loss ended Barnsley's superb home record of six league wins in a row and saw them drop down to eighth in the table.
Adam Hammill returned to the starting eleven following suspension and replaced the ill Lloyd Isgrove. Sam Winnall was fit enough to return to the bench.
Barnsley were behind inside just four minutes. Daniel Bentley lofted the ball long and Jack Payne slipped by Marc Roberts and finished coolly past Adam Davies.
Barnsley looked to have a good shout for a penalty when Marley Watkins cut inside and his shot was diverted wide by Adam Barrett but only a corner was awarded.
Payne went close again at the other end as Barnsley continued to look shaky in defence.
They were carved open again minutes later but fortunately the unmarked Anthony Wordsworth's effort cannoned off the bar.
Barnsley were then given the perfect chance to get level when Ashley Fletcher was brought down for a penalty by Southend 'keeper Daniel Bentley who was yellow carded.
Conor Hourihane, who had put Fletcher through, dragged his effort wide of goal to give the visitors a let off.
Alfie Mawson fired a free-kick straight at Bentley and then into the wall either side of the break.
Winnall was brought on for Harry Chapman early in the second half as The Reds huffed and puffed for an equaliser.
Watkins headed wide from a Hammill cross and then Hammill fired a free-kick into the wall.
Winnall flashed an effort wide but Southend sealed the win late on with substitute Michael Timlin smashing in from the edge of the box.
