Nigel Clough says the Blades must learn lessons from Saturday's home defeat against Crewe Alexandra.
For the second time in the month of March, United succumb to an injury-time goal when they looked set to take at least a share of the spoils
Reflecting on conceding late in the day again, Clough remarked: "People might take this negatively, but they shouldn't. Just like against Peterborough, if we aren't to win the game, we take a point and move on to the next game.
"If we had seen those two games out properly we would be at least two points better off, that's got to be something we learn from.
"The winning goal was slightly fortunate; it swerved a bit and took a nick of Paul Coutts's head too on the way through, but the lad got a shot off too easy from the corner."
Clough, who revealed all three substitutions at the weekend were enforced, due to injuries and fatigue, added:
"There was a frustration amongst everyone on the final whistle, not just the fans.
"There is nobody more frustrated than the players and management because we have lost a game where three points would have really strengthened our play-off position.
"Ryan Flynn and Jose Baxter both came off with injuries, whilst Steven Davies was tiring after a very busy week. We'll see how they are during the week and how they respond to treatment.
"We have made things more difficult for ourselves now, but it remains in our own hands, we are in the play-offs by five points with seven games remaining and a better goal difference than our rivals."