Spalding United manager Dave Frecklington vowed to make changes and take full responsibility after the title dream was effectively ended.
The Tulips missed a chance to close the gap at the top of the table as they conceded a last-gasp winner at Carlton Town on Tuesday night.
Frecklington had already accepted that they needed six points this week to keep alive any realistic challenge for the championship.
Spalding are second going into Saturday’s home game against Romulus but Witton Albion are one point behind with five games in hand.
Shaw Lane remain six points clear in the Evo-Stik Northern Premier League First Division South and the Tulips have now played four more games as they enter the final third of the season.
Frecklington was furious following the 4-3 defeat, admitting: “We didn’t start well enough and even at 3-3 we were lucky to be back in it.
We would be fortunate to finish in third or fourth place playing like that.Dave Frecklington
“We would be fortunate to finish in third or fourth place playing like that.
“I’m absolutely shocked by the performance. I have to look at certain individuals and I had to take off three of our better players.
“We brought on a 43-year-old (Terry Fleming) and a 17-year-old (Jonny Lockie) to change the game. They were excellent in giving us a different dimension.
“But four or five of our big players were miles off it for whatever reason.
“We let them have a week off after the games against Chasetown and AFC Rushden & Diamonds. That won’t be happening again.
“I got it wrong. I’m totally to blame. I picked the team so I take full responsibility for the result and performance. Big players didn’t turn up. I’m angry, frustrated and shocked. I’m absolutely disgusted.”