Wayne Rooney claims Derby were denied the chance to secure a first home win in the Championship since June when they were held to a goalless draw by injury-hit Stoke.
Derby's interim manager believes referee Andy Woolmer should have pointed to the spot when Lee Buchanan went down in the second half.
Rooney had seen Derby dominate possession for long periods but a lack of quality allowed Stoke to restrict them to few chances.
The best fell to Kazim Colin-Richards in the 22nd minute but after going round Josef Bursik, his shot was cleared off the line by James Chester.
Stoke rarely got out of their half before the interval and although they improved in the second half, they did not force David Marshall into a save.
Bursik had to turn over a Matt Clarke header but Derby thought they should have had a penalty in the 65th minute when Buchanan went over but the referee baffled everyone by awarding a drop ball to Stoke.
Rooney said: "I think he's made a mistake and I think he knows that. I appreciate it's very difficult for referees to get all the decisions right, I completely understand that.
"But this decision is so obvious that the referee, the two linesmen and the fourth official, someone has to see it and communicate with each other to come to the right decision.
"The referee explained there was contact but he didn't feel it was a penalty. Now if a player jumping on another player's back is not a penalty then maybe I need to go through the rule book and find out what the rules are exactly.
"You can accept mistakes so I think the referee has seen he's made a mistake and I'm sure he'll hold his hands up to that.
"It's frustrating not to get the three points. First half we played really well and created chances and should have scored.
"Second half we didn't start well but then I felt we grew back into the game and maybe could have gone on and won.
"I think we deserved the three points but we are building a platform with three clean sheets and now we have to demand more from our attacking players to start scoring."
Stoke manager Michael O'Neill didn't think it was a penalty.
He said: "It looked to me like a fairly clean tackle and having seen it back that's still what I think it was.
"I don't think it was a dive either. To be honest I don't think it was a penalty or a dive so I suppose in a roundabout way he got to the right decision and there probably wasn't a decision that needed to be made in that situation.
"First half we were second best in terms of possession and territory. Second half we competed far better, we got up against the game but overall given where we are as a squad and the injuries we have it's a hard-earned point and one we will happily take.
"The squad has been stretched and certainly the players that are missing at this minute are big players for us. On the day it was important we didn't lose the game so a clean sheet and we take a point away."
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