Shane Long put the Royals ahead before they conceded a late goal yet again when Andy Griffin rashly challenged Daniel Bogdanovic in the area and the substitute got up to net the resulting penalty.
McDermott said: "No way was it a penalty. It was a long way off. We thought we should have had a penalty with a handball but let's not talk about the ref.
"We felt that you don't come to Sheffield United very often and dominate the way we did.
"I thought our shape was good. We had chances, we couldn't get the second goal after we got the late first goal.
"All we can do is keep performing the way we're performing and if we do that and keep creating chances then the wins will come, I'm absolutely sure about that. Sometimes the game can be be very, very frustrating and it certainly feels like that at the moment and it's a difficult time results-wise for us but I can't fault our players."
Source: PA
Source: PA