Skipper Billy Sharp says United must focus on the 'positives' of this season, despite falling short in the quest for a play-off place.
Speaking after Saturday's narrow loss to Preston North End at the Lane, Sharp remarked: "We've come a very long way in two years, but it's disappointing we couldn't get a win for the fans.
"I thought we played really well, particularly in the second-half, but the goal killed our momentum.
"Even then we had all the play, we tried and tried, but Preston put bodies on the line and kept the ball out."
United's number 10 added: "The timing of their goal hurt us, they retreated and scrapped for each other and deserved some good fortunate, but we're disappointed that we've ultimately fallen short in the last few weeks.
"Overall though it has been a positive season and we have to focus on those positive as we begin to build for next season."