Jack Marriott scored for the second game running as Derby ended Sheffield United’s unbeaten run with a 2-1 victory at Pride Park.
The striker also set up Craig Bryson for one of the quickest goals in Derby’s recent history to put them on course for a first league win in four.
United had won their previous four Championship matches and they hit back to equalise before half-time through Chris Basham, only for Marriott’s strike to take Derby up to fifth in the table.
Some spectators were still taking their seats when Derby went ahead after only 18 seconds, before a United player had touched the ball.
Craig Forsyth started a move that involved six team-mates and ended with Harry Wilson whipping in a cross from the left that Marriott laid off to Bryson, who swept it past Dean Henderson from 15 yards.
United boss Chris Wilder will have wondered how his team were caught sleeping and they came close to conceding again when Henderson’s clearance was charged down by Marriott, but the ball went wide.
The visitors settled and had periods of possession without creating a clear chance, although Basham almost connected with a low Kieron Freeman cross.
United had another chance when Forsyth brought down Freeman on the edge of the box and a clever free-kick sent Mark Duffy in behind but he overhit his cross. Enda Stevens then surged through on the left but his cross-shot was held by Scott Carson.
Derby had to make a change in the 36th minute when Bryson was replaced by Tom Lawrence.
United had been knocking at the door and they equalised in the 41st minute when John Fleck pulled Derby’s defence apart on the left before crossing low for Basham to fire into the roof of the net from six yards.
The first half ended frantically, with Henderson saving from Marriott before Duffy fired just wide at the other end.
Derby went close in the 54th minute when Jayden Bogle played in Lawrence but his shot was deflected behind, and Mason Mount fired wide after turning past two challenges.
But Derby were starting to stretch United and they regained the lead in the 77th minute when Forsyth cross to the near post and Marriott steered it across Henderson.
United almost equalised six minutes later when Carson fumbled a cross and the ball was scrambled off the line before the keeper recovered to push David McGoldrick’s shot behind and preserve Derby’s lead.