Nigel Clough admitted United's performance in Saturday's 1-1 with Oldham Athletic at Bramall Lane 'wasn't good enough'.
Speaking after Jamal Campbell-Ryce's second-half goal cancelled out Jonathan Forte's first-half opener, a frustrated Blades boss was at a loss following a below par display, but praised the effort of the Latics.
Clough remarked: "It wasn't good enough, we are very disappointed with the performance, especially given how consistent we have been in recent weeks.
"In that context it is a good point having fallen behind and having too many players not at it on the day, but we are still frustrated at the performance.
"We knew Oldham were a good side before the game, they were full of confidence and in the first-half they were the better side and could have been more than one goal in front at the break.
"Oldham were bright on the ball and lively going forward, but we conceded a very soft goal, with the experience of our two central defenders we don't expect to give such goals away."
The Gaffer added: "Jose Baxter was struggling at half-time with a whack or two he had taken to his back, so we don't take any credit for the introduction of Jamal Campbell-Ryce as it was an unforced change.
"With his first contribution Jamal scores, after that he didn't put a cross into the box.
"We are six points off the leaders with a game in hand, despite a disappointing performance, so things aren't too bad, but we know we have to be better than that."