Forest were hammered by the Clarets 5-0 at the weekend, with skipper Perch adamant his team-mates must - and will - improve their efforts to stay in the Championship.
"We have to be at least 50% better than that for the rest of the season," he told the Nottingham Evening Post.
"We showed our resilience, our fighting spirit against Swansea, Reading and Preston. We just have to do that again.
"We are confident we can get out of trouble. But for some reason, we have not shown what we can do one bit in the last two games.
"We have to work hard in training and make sure we react in the right way."