A stunning 78th minute strike from Derby County forward Patrick Bamford condemned Sheffield Wednesday to a second successive league defeat at Hillsborough.
The result leaves Wednesday 17th in the Championship and without a win in their last 10 league meetings with Derby.
Boss Stuart Gray made five alterations to the team who were well beaten by Wigan Athletic last week, handing starts to new signings Gary Gardner and Leon Best.
Having shrugged off a hamstring problem, Glenn Loovens was given the nod to partner Miguel Llera at the heart of the Owls rearguard. Giles Coke and Michail Antonio were also recalled.
Jose Semedo, Adedeji Oshilaja, Atdhe Nuhiu, Benik Afobe and Jacques Maghoma dropped out.
Derby County, in fourth position in the standings, named an unchanged starting line-up.
It was Wednesday who threatened in the early stages with skipper Loovens seeing his downward header from Chris Maguire’s corner hacked off the line by Craig Forsyth.
Gray’s men fashioned half an opening in the 20th minute when Best, making his third Wednesday debut, flicked on Chris Kirkland’s clearance straight into the path of Antonio only for his strike to be deflected wide by Andre Wisdom.
At the other end, Craig Bryson then dragged a shot off target from an acute angle after the hosts only partially dealt with Will Hughes’ free-kick. Hughes, an England Under-21 international, waltzed past Llera before firing straight at Kirkland.
Much to the home fans annoyance, referee Darren Bond cautioned Llera following an aerial duel with former Wednesday shot-stopper Grant.
Gray was forced to throw on Jeremy Helan just before the interval after Kieran Lee picked up an injury.
Half Time - 0-0
Wednesday made a bright start to the second period as Antonio cut inside from the left flank and struck a low right foot effort which Grant did well to cling on to.
Moments later, Maguire’s corner was cleared off the line at the back post by Bryson.
Derby were being put on the back foot due to their inability to keep possession and Forsyth became the latest player to go into the official’s notebook after bringing down the lively Antonio on the right wing.
Just after the hour mark, Antonio turned smartly just outside the edge of the box and let fly but Grant parried his drive out for a corner.
Antonio continued to be Wednesday’s main goal threat and he was again denied by Grant after skipping past several Derby challenges.
With 12 minutes remaining, Derby broke the deadlock through Bamford, whose spectacular 20-yard shot went in off the crossbar. It was the Chelsea loanee’s fifth goal in his last six outings for the Rams and his 22nd of the campaign.
Antonio summed up Wednesday’s frustration in added on time when he blazed over after neat flick on by substitute Benik Afobe.
Sheffield Wednesday: Kirkland, Palmer, Loovens, Llera, Mattock; Maguire, Lee, Coke, Gardner; Antonio, Best. Substitutes: Martinez, Maghoma, Helan, Lavery, Afobe, Nuhiu, Hutchinson.
Derby County: Grant; Wisdom, Buxton, Keogh, Forsyth; Eustace, Hughes, Bryson; Bamford, Martin, Ward. Substitutes: Legzdins, Hendrick, Russell, Sammon, Whitbread, Bailey, Thorne.
Referee: Darren Bond (Lancs)