Roy Keane gave a successful first half-time team talk as Sunderland boss, as his new team fought back from a half-time deficit to see off Derby.
Keane tasted victory in his first game as Sunderland boss
The Rams took the lead on the stroke of half-time as Matt Oakley stabbed home after Steve Howard's cut-back.
But Chris Brown poked home an equaliser after an almighty goalmouth scramble on the hour mark.
And three minutes later, Ross Wallace found space in the left side of the box and swept home a fine low shot.
Derby manager Billy Davies:
"We started the second half brightly but then the lack of confidence set in again and we didn't believe we could do it.
"We lost the game because of two minutes of madness.
"We have got to get into the habit of grinding out 1-0 results or believing
we can go out in the second half and score more goals."
Sunderland manager Roy Keane:
"I had very little to say at half-time except to keep their heads and trust one another.
"It was a great test of character and they reacted exactly the way I thought they would.
"I told them when I took over that it is all about character and if you have
got it you will go a long way."
Derby: Bywater, Edworthy (Bolder 88), Leacock, Michael Johnson, Camara, Barnes, Oakley, Smith, Peschisolido (Seth Johnson 56), Howard, Lupoli.
Subs Not Used: Grant, Malcolm, Nyatanga.
Goals: Oakley 45.
Sunderland: Alnwick, Delap, Cunningham, Varga, Robbie Elliott, Liam Miller, Kavanagh, Whitehead, Wallace, Connolly (Stephen Elliott 84), Brown.
Subs Not Used: Ward, Hysen, Leadbitter, Neill Collins.
Booked: Varga, Brown, Delap, Wallace, Kavanagh.
Goals: Brown 62, Wallace 64.
Ref: A Bates (Staffordshire).