Defeat to Southend on Saturday means the Grecians are four points behind arch rivals Plymouth in the race for seventh place with just two games left.
But ahead of the trip to Hartlepool Tisdale says he has to keep believing that they can reel in the Pilgrims.
“We’re in the hunt because it’s possible,” Tisdale told BBC Radio Devon.
“It’s a lot less likely than it was a week ago but it’s still possible so what do we do – give up now?
“No, of course we don’t, we carry on.”