The Dons had a chance to climb out of the relegation zone when they travelled to Port Vale on Tuesday night, but were on the wrong end of a chastening 3-0 defeat by the leaders.
That reverse ended a run of five matches without defeat and Ardley expects a reaction this weekend.
"We did not play with enough quality, conviction or belief," he said.
"I told the boys afterwards that we have to make sure we know what we are doing on Saturday and put in a performance.
"I thought Port Vale were very good at what they did and we struggled to cope. We have to re-group and go again at Chesterfield."