Nigel Clough admitted that United we very fortunate to leave Essex with all three points on Tuesday night.
An amazing turnaround, culminating in three goals in five minutes with time running out, saw the Blades beat a shell shocked Colchester United 3-2 at the Weston Homes Community Stadium, with Ben Davies netting either side of Ryan Flynn's equaliser, the winner coming from the penalty spot.
But Clough was honest in his assessment, admitting luck certainly favoured the Blades.
He remarked "It was a very poor performance, apart from the last 15 minutes, we aren't happy with a lot of things that went on.
"We were poor in possession for the first 75 minutes and when we did get in good positions the quality of service into the penalty area was very disappointing.
"We had to readjust having lost Baxter, Murphy and Campbell-Ryce, but we should have had enough out there to do much better for long periods, it was only the introduction of Stefan Scougall that sparked us into action."
The Gaffer felt both of the hosts goals were avoidable, but acknowledged that his goalkeeper appeared to be fouled for the U's second, scored by Freddie Sears.
Clough added: "We are also bitterly disappointed with the goals we conceded and Colchester probably should have had more.
"But we believe Mark (Howard) when he says the ball was kicked out of his hands for the second one.
"If Mark had made a genuine mistake he isn't the type of lad to go chasing the referee, but we have to accept things and make sure we improve."