The Reds are beaten again as the Rams grab three goals and three points at a bitterly cold Oakwel
Late first half goals from Tom Lawrence and Matej Vydra rocked the Reds who'd been on top in the opening period but couldn't grab a goal for their work.
A second half Andreas Weimann strike sealed the deal for the high-flying Rams.
Paul Heckingbottom once again shuffled his pack in search of ending this barren run, with starts for Mamadou Thiam and Gary Gardner and the side lining up in a 4-4-2 system.
And it was a bright opening half hour for his side who tested Rams 'keeper Scott Carson through Harvey Barnes' 25-yard curler, brilliantly turned behind by the former England goalie.
Thiam tried his luck from range but Carson held on well.
Those two linked up well after 35 minutes and Thiam's ball found Barnes surging into the box but his cross/shot evaded the stretching Tom Bradshaw at the far post.
Derby had a few corners but without threatening other than a Craig Forsyth header over the bar.
But on 39 minutes the visitors took the lead.
After a scramble inside the box, Reds defenders failed to clear and Lawrence was on hand to take full advantage and fire beyond Adam Davies from eight yards out.
It was 2-0 on the stroke of half time and again, it was an inability to clear their lines that cost Barnsley.
This presented Vydra with a golden opportunity which he lapped up, firing low into the net from a similar position to the first goal.
HALF TIME: Barnsley 0-2 Derby
The game was scrappy upon resuming after the break, and it wasn't until Brad Potts crashed a left-footed drive off the bar that the game sprung back into life.
On 61 minutes Adam Hammill and George Moncur replaced Potts and Gardner, as Heckingbottom looked to get his side back into the match.
Five minutes later and Hammill went close when his trademark run and shot cutting inside flew just past the post.
On 70 minutes it should have been over when Forsyth somehow blazed over for Derby when it looked easier to score.
Ike Ugbo replaced the impressive Thiam on 71 minutes.
The on-loan striker nearly made the perfect impact as Barnes' cross fell perfectly for him inside the six-yard box but his shot was too close to Carson who pulled off a great diving save.
The Reds would rue that missed opportunity as Weimann put the game to bed when he fired home from 20 yards out with nobody able to close him down on the counter attack.
Unfortunately, the game petered out into nothing and it's now five defeats on the spin for Heckingbottom's young side with consecutive West London trips next up on the horizon.
FULL TIME: Barnsley 0-3 Derby
Reds: Davies (GK); McCarthy, Pearson, Lindsay, Yiadom; Potts (Hammill 61), Gardner (Moncur 61), Williams; Barnes, Bradshaw, Thiam (Ugbo 71).
Unused: Townsend (GK), Fryers, McGeehan, Mallan.