Paul Sturrock insists he is running out of patience and is already looking for replacements after Southend's 2-0 defeat at Aldershot.
The Shrimpers relinquished top spot in League Two with the defeat.
The Shots, 14 places below Southend before kick-off, triumphed through Adam Mekki and Josh Payne's penalty to send the Shrimpers down to third in the table.
"Gutless is the word I would use," fumed Sturrock. "This team needs a freshness as far as personnel is concerned. We can't seem to push ourselves to get ourselves in the right manner.
"This was just like the Rotherham debacle. At the end of the day I cannot tolerate this any longer. If we've got ambitions of winning leagues, first and foremost we've got to turn out performances and results.
"We were second best and a change of personnel is what we need. There are people here who have had several chances to show me they can do a job, and again we've come up short.
"Aldershot had a couple of new players and had shape and enthusiasm. Too many of our players are showing inconsistency. We played 90 minutes and failed to hit the target. Every game is a cup final now but we've let ourselves down. I judge my performance as a manager on selection and getting the selection right."