Manager Paul Sturrock told his players that they had let everyone down after Tuesday’s 2-1 defeat against Aldershot Town.
Blues performance against the Shots was not at the level the experienced Scotsman would have expected.
And he has told his team to put things right against York City on Saturday afternoon at Roots Hall.
“I’ve had some harsh words with the players and they realise they let everyone down,” Sturrock told the official website.
“We have a quick opportunity against York to put that right.
“They have a settled team and we need to be at the top of our game if we want to get anything from it.
“Some players will get an opportunity to put things right by selection and others will get the chance to stake a claim.”
Meanwhile, Sturrock was also grateful for the manner in which Blues supporters vented their feelings following the defeat.
A crowd of 4,225 supporters witnessed United’s third home defeat of the season.
And Sturrock hopes those same fans will continue to be his sides’ 12th man.
“Our home form has been the disappointing thing this season,” he said.
“We have to make sure that we get back on the rails at Roots Hall.
“The fans were fantastic the other night. I have asked all along that they vent their frustrations at half time and after the game and that is exactly how it has been over the last few games.
“The players are very appreciative of that. There will be one or two who want to have their say during the game but I’d like to think some of the supporters around them would dampen them down.
“I want the fans to be our 12th man and I know the players are appreciative of the singing in the north stand.”
Southend look set to be without Mark Phillips against York after he suffered a reoccurrence of his groin problem midweek.
Luke Prosser and Ryan Leonard are also unavailable, whilst Michael Timlin’s ankle injury should also keep him out of action.
“Mark Phillips won’t make the game,” he confirmed. “He was probably brought back too quickly and Prosser and Leonard are struggling as well.
“Timlin is still having issues with his ankle so I would be very surprised if any of them came out of the treatment room.”
Despite those absentees Sturrock hopes to be boosted by the arrival of a new signing ahead of the match.
The Blues chief is expecting to sign a midfielder on loan whilst striker Barry Corr could return to the bench following a groin injury.
“We might have a new face for tomorrow,” he said. “At this moment in time we need to strengthen a lot in that central area.
“We need one or two for there and although I don’t think we will get another in for Saturday I am lining up some others to bolster the squad.
“I am hoping Barry will come back into training on Friday and potentially be on the bench this weekend.”