The Blues could have got out of the bottom three last night but lost their game in hand at home to Wigan Athletic, meaning that they still haven't won at home since October 1 - a run of 18 winless games at St Andrew's.
That means that they occupy the third relegation spot going into Saturday's final round of fixtures, but Clark is confident that they can beat the drop.
"[The players] have got to be up for it, up for the occasion," he told the Birmingham Mail ahead of their trip to Bolton Wanderers.
"There is no point feeling down in the dumps, no point feeling sorry for ourselves. We have got to lift ourselves."
The Blues are one of four sides who can be relegated on Saturday and start the day with by far the best goal difference and one point behind Doncaster Rovers, two adrift of Millwall and three behind Blackpool.