A 95th minute shot from Cauley Woodrow was enough for Barnsley to salvage a point, despite the home side leading early on through Aapo Halme.
The Rams made a quick comeback before half time, with Chris Martin getting his third goal in as many games and Tom Huddlestone slotting home a penalty.
Before the game started, there was a shock in the side that Phillip Cocu named. Both Tom Lawrence and Mason Bennett were included in the squad, the former in the starting line-up, despite both players’ court case in a few weeks.
On the pitch though, Barnsley threatened early on. Krystian Bielik gave away the ball, which landed for Woodrow. The number 9 scuffed his shot against Kelle Roos’ far post, an early sign that Derby weren’t in for an easy night.
Just four minutes later, the home side took an early lead. Alex Mowatt’s free kick from the right swung in for centre back Halme to head over Roos to put the Reds a goal up within the first 13 minutes.
It was a similar tale of set pieces and chaos in the Derby box as the game went on. Woodrow came close again, latching onto a Mowatt corner and forcing the Rams to clear off the goal line just 20 minutes into the game.
Cocu’s side then started to grow into the game. Jamie Paterson’s cross on the right found Curtis Davies in acres of space, but the new captain couldn’t steer his header on target for what seemed like a certain goal.
The away side finally unpicked the lock in the 34th minute. Tom Huddlestone’s tremendous chip ball over the top of the Barnsley back line found Paterson. The number 7 squared the ball for none other than Martin, who in his current form, was never missing to make it his third goal in three games.
Just ten minutes later, the Rams had an opportunity to take the lead. Pantomime villain Tom Lawrence was brought down in the box by Mads Andersen and was awarded a penalty. Huddlestone stepped up, calmly sending Collins the wrong way to give Derby the lead heading into half time.
The second half was very similar to the first, as both had chances to take a real grip of the game, but neither did. Martyn Waghorn’s free kick tested Collins early in the second half, forcing a low save to the goalkeeper’s left.
The Rams continued to look threatening, especially in counter attacking situations, however they couldn’t quite manage to find the final ball that would surely kill the game off.
The last quarter of an hour were a time for Derby to defend resolutely. A scramble in the Rams’ box from yet another set piece saw fullback Jayden Bogle called into action to clear the ball off the line as the game got more and more tense.
Just a minute after the goal line clearance, Roos was called into action to tip the ball over the bar from a Mowatt free kick.
Into the last minute of added time, Derby’s resolute defending finally collapsed. Another well worked set piece caused chaos in the box, with Conor Chaplin’s shot from the edge taking a final touch from Woodrow, who wheeled away celebrating a last minute point.
The Rams will look bounce back from the late sucker punch when Luton Town visit pride park on Saturday.
Derby County: Roos, Bogle, Bielik, Davies, Lowe, Huddlestone (Clarke 45), Holmes (Bennett 89), Patterson, Waghorn, Lawrence, Martin (Knight 79).
Unused Substitutes: Dowell, Jofezoon, Hamer, Malone.