Ian Allinson has warned his misfiring St Albans City players they are playing for their futures at the club after a 3-2 loss against Truro City on Saturday.
Defeat at Treyew Road saw the Saints fall six points off the play-off places as haphazard defending allowed relegation-threatened Truro to record a surprise win.
City have now conceded 28 goals in their last 11 matches, prompting Allinson to issue a stark warning to his players.
“Without a shadow of a doubt, if we don’t start improving over the next couple of weeks, some of these players will be playing for their future,” Allinson said.
“I have got to put these players under immense pressure now. We can’t keep turning up game after game and keep conceding goals.
“The players have worked extremely hard, it is just the naivety and stupidity when it comes to defending.”
St Albans trailed 1-0 to Stewart Yetton’s 28th minute strike before levelling through Tom Bender five minutes after the restart.
However, some more sloppy defending handed the initiative back to Truro less than a minute later as Arran Pugh struck for the hosts.
Charlie Walker continued his strong form to restore parity in the 54th minute.
Allinson's side looked well set to take at least a point from the match, but a rush of blood from George Cassey saw the defender concede a penalty which Tyler Harvey converted.
Allinson's appraisal of his side's defending was frank as he criticised cheap goals which undermined the Saints' strong attacking display.
"The goals we conceded weren't good enough and we have to defend better if we are going to win games of football," he said.
"The manner of the goals were cheap and the penalty, for me, is an absolutely awful goal.
"It was a very poor goal at a time when we were in charge of the game and looked like we were going to go on to win it."
Chelmsford City's 4-3 win over Concord Rangers opened up the gap between the Saints and the play-offs on Saturday and Allinson's men are playing catch up.
The Clarence Park club will need to correct their ailing form quickly if they are to maintain hopes of making the play-offs.
They have just one win in their last 10 National League South games and Allinson accepts their current form is not good enough.
"At the moment we look like a team that would be fighting relegation if we were in any other situation," he said.
"I can't ask the players to put in more of a shift and we have done everything right in terms of preparation. It is just the issues with defending."
City were play Wealdstone at home on Tuesday night.
They follow that match with clash against Bishop's Stortford at Clarence Park on Saturday.
City will be hopeful of taking three points from the meeting with a side in the drop zone after a 4-1 loss to Eastbourne.