Alfreton Town manager Nicky Law was furious with his side's display after they lost their penultimate game of the season, against Newport.
The Reds were already assured of their Blue Square Bet Premier survival after a superb revival which brought six wins from eight games in March.
But Law told BBC Radio Derby: "That was not an acceptable performance [against Newport] whether we were safe or not.
"That was back to when we were a struggling side earlier in the season."
Law was delighted with their season as a whole, but said Saturday's loss had just confirmed his opinion about some of his players.
"It's been a remarkable turnaround," he added.
"There was not a lot on the game so we didn't want it to die off, but that's what happened. That was the big disappointment. There are players playing for contracts and I was looking for a spark and I didn't see it.
"It was lacklustre and we looked tired. I probably made my mind up on a few answers I needed. I wanted to make my mind up on decisions and it proved that my opinion was right."
Alfreton end their season with a home game against Bath City on Saturday.