Dunston UTS stunned the in-form National League North club as they bridged a three tier gap to win 4-3 against the ten men.
Johnson said he didn’t know where the embarrassing loss came from after playing so well throughout September.
“They play liked it was their biggest game ever,” he said. “Congratulations to them, they were excellent.
“To play at the level they do and to beat a side from our level, you have to say well done. I can’t take anything away from them.
“But a lot of it was of our own making and the winning goal was a foul. We should have taken the 3-3 but some of our sloppy play was terrible.
“What happened at the start of the second half I don’t know. The sending off was of our own making and it’s all cost us.
“I’ve not seen any of our players do what they did take over the past month. We had chances with ten men but we have given the ball away so much. It’s a difficult one to take.”