Manager Frank Lampard was naturally disappointed following Derby County's 3-1 defeat at Bramall Lane against Sheffield United on Boxing Day.
Harry Wilson equalised with a trademark free-kick early in the second half after Blades striker Billy Sharp gave the home side a first half lead with a close-range header.
However, goals from David McGoldrick and Leon Clarke saw the Blades run out winners.
Lampard told RamsTV: “We were in the game in the first half. They didn’t have many opportunities and they generally do create a lot here, but they didn’t.
“We had some good chances, notably when Harry Wilson went around the goalkeeper, but I’m disappointed. It was a tough match and we were back in it at 1-1 but after that we can’t be happy.
“We made mistakes for their goals and we can’t be happy with the way we let the game go away from us when we just got back in it so that’s things we need to address.
“When you allow a free header in the box, which is the first goal and the third goal, and it was a simple second goal which we gave away, which shouldn’t be allowed at our level.
“We have players like Harry Wilson, Jack Marriott who can produce for us but when the game goes away from you then it’s hard.
“It was a tough game. It’s not easy here but they were at it more than us, the atmosphere in the stadium changed but we have to be big boys when that happens and not make those mistakes and keep things simple, but we didn’t.
“You can come to Sheffield United and lose, it happens, they are a good team but there are reasons in the game that you think ‘it’s too easy, we shouldn’t make those mistakes’, but to address it, we need to go again in three days time.”
Left-back Scott Malone missed the game due to injury after sustaining an injury late in the weekend's 1-1 draw at home to Bristol City.
Lampard revealed: “Scott will be out for a few weeks at least. It’s a muscle injury. We have issues with left backs, we know that.
“We’ve Craig Forsyth long-term and Marcus Olsson coming back from a spell out too. Calum Macdonald from the under-23s is injured at the moment too and Max Lowe is coming back from his loan at Aberdeen but he has a small injury as well.
"We have to adjust around it but it is what it is.”