The Hawks' midweek win at Dagenham & Redbridge has them just two points adrift of safety.
And Bradbury knows, although a win against the Spireites won't be easy - they've already shown they have what it takes.
"Anything less than what we gave against Dagenham won’t be acceptable," he told The News, Portsmouth.
"I am looking for the same energy and willingness to do that extra bit for each other. Tackles will need to be made all over the pitch and that is something we did brilliantly in midweek.
"If we maintain our standards then it will give us every chance of getting a result."
Trips to Aldershot and Maidenhead in the coming weeks also present good opportunities to gain ground on sides around them.
And Bradbury said his side shouldn't be scared of the challenge that awaits.
"We have got a few games now against teams in and around us," he said.
"These are big points on offer. It is vital we play with the same intensity and tempo.
"We must look to get on the front foot early and impose ourselves on the game."