Frank Lampard insisted referee Keith Stroud had cost Derby victory after they were denied a penalty in a 0-0 draw with rivals Nottingham Forest at Pride Park.
Rams midfielder Tom Lawrence appeared to be fouled in the area by Tendayi Darikwa midway through the first half, but Stroud waved away the appeals.
The visitors then carved out the clearer chances, with Sky Bet Championship top scorer Lewis Grabban denied by Scott Carson on the stroke of half-time and Joe Lolley hitting the bar late on.
Derby should have had a penalty after 19 minutes when Darikwa clumsily kicked Lawrence in the box, and Lampard was adamant a foul had been committed.
"I think that the most staunch Nottingham Forest fan in the far side of the stadium thought that was a penalty," Lampard said.
"The easiest penalty to give is one where the striker gets a touch, clearly, and the defender follows through and catches him in the waist, clearly.
"The referee is on his own in his opinion that wasn't a penalty.
"It was a game-changer because, albeit it was a fair result in general play, that was the goal that wins us the game.
"I think both teams gave everything and, in general play terms, pretty fair for the point."
In a keenly-contested game of few clear chances, Tom Huddlestone diverted a Richard Keogh header over the bar before Carson stuck out a leg to thwart Grabban after the latter had been sent clear by Ben Osborn.
Lolley tested Carson again after 65 minutes when his curling effort from range had to be tipped over by the ex-England keeper.
Harry Wilson stung the palms of Costel Pantilimon in the 76th minute when he met Jack Marriott's cross with a fierce volley.
With eight minutes remaining Joao Carvalho found Lolley, who clipped the top of the crossbar with a curling effort after cutting in from the right.
The hosts could have won it in stoppage time, but substitute David Nugent failed to get enough purchase on his header to seriously test Pantilimon.
Forest manager Aitor Karanka refused to criticise the referee, and felt his side were worthy of at least a point after a strong second-half showing.
"I don't know if it was a penalty," he said. "The referee was closer than me and if he made that decision it's because he felt it was the right decision.
"I think we approached the game well.
"The main thing today was for our crowd to come back home proud of the team, and I think they are doing."