Town are now without a league win in 13 games and are just four points above the relegation zone after losing 3-1 at Accrington.
"It was a poor result and a poor performance," said Johnson. "We had done a lot of work on tactics this week but unfortunately on the day, the lads didn't step up to the plate.
"We had a couple of early chances but you could see, when they scored, they grew in confidence while ours faded.
"There were a few shrinking violets and they have now got cup finals all the way until the end of the season - we have some very big games.
"A few couldn't get involved in this game and did not do enough and players need to stand up and be counted."
Source: PA
Source: PA