Derby failed to extend their lead at the top of the Championship after Stoke secured a victory with first-half Danny Higginbotham and Dominic Matteo goals.
Derby's David Jones cannot find a way through the Stoke defence
Higginbotham scored from the spot after Dean Leacock inexplicably handled Lee Hendrie's corner in the 13th minute.
And another Hendrie corner resulted in the second as Matteo headed home.
Despite Matt Oakley's shot shaving the bar and Derby laying siege to the away goal with Steven Howard and David Jones going close, County found no way back.
Derby boss Billy Davies:
"It is just one game. We are still top and many teams would like to swap places with us and be where we are now.
"The pressure is bigger when you are the ones out in front. I want to be top at the end of the season, not now.
"It's a great challenge, we've 13 games left, Sunderland on Saturday is a big game and losing here may not be a bad thing."
Stoke boss Tony Pulis:
"After our recent results we just needed to get a win. It is a weight off our shoulders.
"It was a great win and I am very pleased. It is a very important result for us to start to build momentum.
"I don't think we have been playing badly recently, we just haven't been taking out chances but here we did."
Derby: Bywater, Edworthy, Leacock (Mears 16), Michael Johnson, McEveley, Teale, Oakley, Jones (Pearson 69), Fagan, Macken (Lupoli 61), Howard.
Subs Not Used: Grant, Peschisolido.
Booked: Leacock, Edworthy, McEveley.
Stoke: Simonsen, Hoefkens, Zakuani, Higginbotham, Griffin, Lawrence, Russell, Matteo (Eustace 63), Diao, Hendrie (Dickinson 85), Sidibe (Rooney 89).
Subs Not Used: Hoult, Martin.
Goals: Higginbotham 15 pen, Matteo 26.
Ref: K Stroud (Hampshire).