After encouraging displays against Championship duo Nottingham Forest and Reading, Northampton were second best against their Blue Square Premier opponents and went down to a 2-0 reverse at the Abbey Stadium.
Only one pre-season fixture now remains ahead of the big League Two kick-off and Johnson commented afterwards: "We had quite a few players who weren't at the races. In fact other than Lewis Young, none of them did anything.
"It was a game that showed us we're not there yet, that's for sure.
"We've got a lot of things to work on. I was going to give them a day off but they'll be in training.
"I thought they might have deserved a day off, they don't now of course and they'll understand that."