Jordan Houghton said it was a downbeat dressing room after Dons lost to Tranmere Rovers on Saturday.
Connor Jennings' second half header proved to be the difference at Prenton Park, after Kieran Agard cancelled out David Perkins' opening strike.
The result drags Tranmere right into the race for automatic promotion, with three points separating Bury, Mansfield, Dons and Rovers with four games to go.
As Dons struggled to create anything on the Wirral, Houghton said the squad were felling low after the result.
"We're deflated and frustrated," he said. "There weren't many chances in the game.
"In the second half, they had the goal and another shot but to be fair, we didn't trouble their keeper as much as we'd have liked. I don't come away from here thinking we've played poorly or got battered, it was an even game, a tough game, but we knew it would be. There are always things to improve on. The main thing was to get a win or a point but we haven't done that.
"We go into every game wanting to win, we didn't set up not to lose or to draw. When you're away, you have to be more reserved, but we have a lot of injuries, so with personnel, it is what it is and people have to fill in. Away, you try to be tighter, but the first half was open and must have been enjoyable for the fans.
"Overall, I'm pleased with the performance, but leaving without points is not good enough."
With two games in four days over Easter, starting with a trip to relegation scrappers Notts County on Good Friday, Dons have the chance to make amends after back-to-back defeats, and Houghton expects more twists in the final four games of the season.
He added: "There are only a few games left and there will still be twists and turns, ups and downs over Easter. We've just got to keep working and plugging away."