The game was at a stalemate after a close-fought first half saw neither side significantly troubling the goals, with midfielder Ebou Adams coming closest for Derby from distance.
Finn Azaz broke the deadlock as he netted for the hosts to give them the lead with ten minutes of regulation time remaining.
Derby return to Pride Park Stadium on Saturday 8th March for the visit of Blackburn Rovers in the Sky Bet Championship (3pm kick-off).
-of-Derby-County-gives-his-shirt-to-a-young-fan--AHPIX-LT.jpeg?crop=3:2&trim=&width=800)
1. Sondre Langas ( 6 ) of Derby County gives his shirt to a young fan.
Derby County were defeated 1-0 by Middlesbrough at the Riverside Stadium in the Sky Bet Championship on Saturday afternoon. | Craig Hawkhead/AHPIX LTD
2. Fans, crowd
Derby County were defeated 1-0 by Middlesbrough at the Riverside Stadium in the Sky Bet Championship on Saturday afternoon. | Craig Hawkhead/AHPIX LTD
3. Fans, crowd
Derby County were defeated 1-0 by Middlesbrough at the Riverside Stadium in the Sky Bet Championship on Saturday afternoon. | Craig Hawkhead/AHPIX LTD
4. Fans, crowd
Derby County were defeated 1-0 by Middlesbrough at the Riverside Stadium in the Sky Bet Championship on Saturday afternoon. | Craig Hawkhead/AHPIX LTD