Danny Wilson is still looking for his first win in his second stint as Barnsley manager after a 2-1 defeat to Derby at Oakwell.
The visitors – backed by a travelling army of almost 6,000 fans – took the lead after eight minutes as Chris Martin scored for the in-form Rams.
After the break, Martin got his and Derby's second, heading home a Andre Wisdom cross.
The Reds pulled one back through substitute Tomasz Cywka but Chris O'Grady missed a golden chance late on as Derby went home worthy winners.
