Super-sub Tomasz Cywka scored for the third game to snatch a point for Barnsley.
Cywka's strike on 84 mins from the edge of the box rescued David Flitcroft's men after they had fallen behind to Charlie Austin's first half strike.
The Reds were fortunate to go down to ten men when Stephen Foster tugged Martin Paterson's shirt when the striker was clean through while Austin's appeal for a penalty was turned down.
Barnsley could have won it late on but Jacob Mellis' long-range volley sailed over while Jim O'Brien's strike was tipped over by Lee Grant.
Despite the brave point, the Reds drop into the bottom three after Wolves won at Millwall.
