Marcus Law was left fuming after Kettering Town turned a winning position into a losing one as their shocking form at Latimer Park continued.
A fine finish from Spencer Weir-Daley gave the Poppies the lead against high-flying Chippenham Town two minutes into the second half.
But Andy Sandell scored from a corner and then Alan Griffin grabbed the late winner for the visitors to secure a 2-1 victory.
It has left the Poppies still searching for a first home win in the Evo-Stik Southern League Premier Division.
And while all the pre-season talk was aimed at a promotion bid, their latest setback has left Law’s team languishing in 17th place - just three points above the relegation zone.
Kettering have won four out of their five away league matches and Law now admits his team have put pressure on themselves to keep that sort of sequence going when they head to Biggleswade Town on Tuesday night.
The furious Poppies boss said: “We have gone from a comfortable position to losing the game and it’s unacceptable.
“The lead up to the corner for their first goal was unacceptable and the defending from it was unacceptable.
“Then, for their winner, we have set up a wall for a free-kick and the ball has gone through it.
“The game was nullified. They cancelled us out and we cancelled them out.
“It looked like one goal would decide it and I felt it would be a moment of excellence or a set-piece that would give either team the lead.
“I thought we produced that moment of excellence. It was a great ball from Lewis Hornby and a fantastic finish from Spencer.
“We were in control of things but we have shot ourselves in the foot yet again. I am getting tired of it and the fans are getting tired of it.
“I have spent 10 years working with a Premier League academy and the mistakes we are making are what I would expect from my under-12s team and if they made them I would put it down to them learning the game.
“Here, we are talking about experienced semi-professional footballers and doing the basics shouldn’t even be brought into it.
“I have sat down with my staff and we have gone through the goals we have conceded in the seven home games we have played in the league.
“And from the 13 we have conceded, I believe there are only two we can give our opponents credit for.
“The rest have come either penalties, set-pieces or individual errors and it’s not good enough.
“We seem to be going through the full repertoire of how to concede goals. It has got to stop because we are getting punished every single time.
“We are putting serious pressure on our away form and we have to go and produce on the road again on Tuesday night.”