There was no dream return to Pride Park for former Derby County player Chris Powell as his Huddersfield Town side suffered a first defeat in eight Championship matches.
Substitute Simon Dawkins ended hopes of a comeback for the 955 travelling supporters in a bumper 27,153 crowd with a 77th-minute strike.
Harry Bunn marked his new Town contract by cancelling out Jordan Ibe's early opener, but the Rams regained the lead when Johnny Russell scored in first-half stoppage time.
Dawkins' strike stretched the lead, and while Mark Hudson headed home deep into time added on, it was a fourth defeat in four trips to Pride Park for Town, who have now failed to win in 21 visits to Derby.
They produced a spirited display, but few would argue with Derby's right to to the points, with Town now aiming to bounce back at Fulham on Saturday.
Manager Powell kept faith with the side which scored a fine 3-0 home win over Nottingham Forest as he went in search of a pair of East Midlands scalps.
But there were two new faces on the bench, with 21-year-old keeper Lloyd Allinson stepping up in place of the illness-hit Joe Murphy and midfielder Radi Majewski coming in.
Derby boss Steve McClaren made three changes as he tried to conjure a response to two consecutive league losses.
In came central defender Ryan Shotton to play alongside former Town loan player Richard Keogh, midfielder Will Hughes and on-loan Liverpool forward Ibe.
Derby made the early running, and Chris Martin and Russell both put shots over before Joel Lynch headed Ibe's piledriver off the line.
The hosts were looking menacing, and it wasn't a surprise when Ibe put them ahead in the seventh minute, planting a Jeff Hendrick pass into the net from 10 yards out.
Hendrick's shot was held by Alex Smithies before Town staged their first real attack after 17 minutes, Nahki Wells' low angled shot being deflected across the face of goal for a corner.
Tommy Smith had to be alert to cut out Cyrus Christie's dangerous cross, then thwart Hughes as Derby continued their onslaught.
But they were stunned by Bunn's 22nd-minute leveller, despatched with real composure after good work by Wells and Grant Holt.
Holt came close with a header from Jacob Butterfield's corner, but Derby were soon back on the attack, and Jack Robinson did well to clear from Ibe.
The left-back made another key clearance as Christie crossed and Hughes lurked, but the home side weren't to be denied.
Town's travelling fans claimed Martin was offside as he slammed a shot into the midriff of a diving Smithies, but there was no whistle and Russell rolled the rebound home.
Martin's penalty-area slip gave Town a let-off as Russell put in an enticing cross early in the second half.
But the visitors were soon pouring forward, and Lynch headed narrowly over from a corner by Butterfield, who then tested keeper Jack Butland with a powerful drive.
Smithies made a good stop from Russell as play switched to the other end, while Town were unable to capitalise as Butterfield swung in a free-kick on the hour.
Bunn then fired over from Holt's pass while it took a well-timed tackle by Lynch to dispossess Derby's Hughes as he bore down on goal.
Wells cut in dangerously in the 72nd minute, only to shoot wide before Smithies plucked Keogh's header out of the air.
But there was nothing the keeper could do to deny Dawkins as he shot home off a post moments after coming off the bench.
Majewski made his first appearance under Powell when he came in as a 83rd-minute replacement for Butterfield.
Two minutes into time added on, Hudson powered home a header, but the final whistle blew moments after the game restarted.