Rotherham United caretaker manager Paul Warne pointed an accusing finger at the referee after suffering derby-day heartache at Sheffield Wednesday.
The battling Millers were beaten by a penalty in time added on as their 35-year unbeaten run at Hillsborough came to an end.
Warne accepted a spot-kick was the right decision, but also claimed a goal his Championship side had disallowed towards the end of the first half should have stood.
“For the goal, I've watched it back numerous times and I cannot see where the foul is," he said. "I can't even see where it might have been. I will go and speak to the referee and he will tell me something I didn't see."
Tom Adeyemi headed home a Joe Newell free-kick but man in the middle Tim Robinson found a reason to rule it out.
Rotherham gave their all and were only moments away from the draw they deserved when Richard Wood fouled Lucas Joao in the Millers area and was sent off before Steven Fletcher despatched the spot-kick.
“My honest opinion is the penalty is a penalty," Warne said. "There is contact from Woody on the player. It is minimal contact.
“It was more a case of the player winning the penalty. Would I be happy if my striker did that in the 93rd minute to win the game? Yes, I would.
“But I don't know how that is a sending-off, I am going to speak to the referee about that as well."
The defeat left the Millers 12 points adrift at the foot of the table, but Warne has impressed in his four games in his interim role and could be handed the reins for an extended spell.
“This game is a big deal for us and it is a big deal for my players. If we have scored a good goal, then going into the break 1-0 it could have been a different story," he said.
"I don't understand what he has seen. It seems harsh on us."
“To lose at such a late stage is bitter pill to swallow, but I will still go home pretty proud. We couldn't give any more.
“My players were true warriors today. I was as proud as punch. Did we get any luck? No. Did they? Well they got a dubious penalty and we had a goal disallowed.”