John Fleck says the Blades must bounce back quickly from Saturday's loss at Derby County.
Speaking in the aftermath of the reversal at Pride Park, the Scottish midfielder admitted it was a missed opportunity for United to regain top spot in the Sky Bet Championship.
He remarked: "It was a disappointing defeat and we've only got ourselves to blame really.
"It was a sloppy start from us and the complete opposite of what we'd said beforehand too."
Fleck added: "To be fair it isn't like us to switch off and start the game slowly, so hopefully it doesn't happen again, but to lose the game just makes it worse.
"We've got to move on quickly though, with a home game on Tuesday, which is now the focus."