Wednesday not so much crashed as rolled over to their third consecutive home defeat as Derby belatedly found a route to goal, doubling their tally for the season with strikes from Rory Delap and the substitute Dean Sturridge, who scored with his first touch.
Wednesday's manager, Danny Wilson, put a brave face on losing to the team which had been immediately above them. "Both teams were nervy and the first goal was always going to be crucial," he said, and so it proved. Wednesday should have scored it, as they had the better of a poor first half and Derby's goalkeeper, Russell Holt, scooped a goal-bound effort from Peter Atherton off his line.
The hopes of Derby's manager, Jim Smith, that the debutant Esteban Fuertes might end his goal drought came to nought as Wednesday's own South American, Emerson Tome froze him out of the game.
Instead, it was another gamble by Smith - playing the wing back Delap up front - that did the trick. Delap and Lars Bohinen had both squandered good chances before they combined to produce the simplest of goals. Delap dallied on Bohinen's long forward ball just long enough to glance up and curl it round Wednesday goalkeeper, Kevin Pressman, after 54 minutes for his second goal of the season.
Having rediscovered the knack of scoring goals, Derby developed a taste for them. Fuertes' replacement, Mikkel Beck, twice went close, sending an angled drive across the face of goal and forcing a smart stop from Pressman, before another substitute put Wednesday out of their misery.
Sturridge had been on the field only a few seconds when he met Delap's cross on the line for a simple tap in. And it could have been worse for a demoralised Wednesday.
Beck hit the post from only two yards after getting his head to Stefan Schnoor's cross and another substitute, Stefano Eranio, brought another point blank save from Pressman.
In mitigation, Wednesday lost their key defender, Des Walker, after only 14 minutes and when their play-maker, Wim Jonk, limped off after they had used their third substitute, they had to play the last quarter with only 10 men.
"We can't get our free-flowing football going because we are desperate for points," said Wilson. Smith's assistant Billy McEwan said: "Delap scored a wonderful goal. It was great to get our first win."
Sheffield Wednesday (4-4-2): Pressman; Atherton, Thome, Walker (Newsome, 14), Nolan; Alexandersson, Jonk, Haslam (Sibon, 59), Rudi; De Bilde (Cresswell, h-t), Carbone. Substitutes not used: Srnicek (gk), Donnelly.
Derby County (3-5-2): Hoult; Laursen, Prior, Schnoor; Borbokis (Sturridge, 78), Bohinen (Eranio, 71), Powell, Johnson, Carbonari; Fuertes (Beck, 65), Delap. Substitutes not used: Poom (gk), Harper.
Referee: M Reed (Birmingham).