Luke Prosser admitted it was ‘not good enough’ from Blues as they were beaten 2-0 by Barnet at Underhill.
Despite a bright start, Blues fell behind in the 30th minute to Jake Hyde’s header and failed to find a way back into the game before Edgar Davids rounded off the scoring for the hosts.
And Prosser, captain for the evening in place of the injured Chris Barker, insisted Blues will need to respond on Saturday against Rotherham.
Prosser said: “That was not good enough out there and we all know that, it was a very disappointing result.
“I don’t think we approached the game in the right way and you just can’t afford to do that.
“We came into the game off the back of a good 2-1 win but that’s irrelevant if you can’t build on it in your next game.
“At the moment we seem to be picking up a win, then drawing and then losing we just can’t seem to put a run together.
“There’s not many games left in the season now so we’ve got to get a run together and get ourselves back in the play-off places.
“Credit to Barnet because they deserved the win, but we know we weren’t good enough and must work hard in training before Saturday.
“We will respond. We have to. We have to get into the play-off places and a win on Saturday can kick start that.”
Prosser praised the Blues supporters who made the journey to Underhill, and apologised to them for the performance.
“The fans are always absolutely fantastic,” he added. “They were again at Barnet and I can only apologise to them for that performance.
“Hopefully they will all be at Roots Hall on Saturday and we can pick up an important win and put on a good performance for them all.”