The Tigers start their Super 8s campaign against Radford’s men, who are at the top of Super League, tonight.
“Theyre tough, they’ve been massive improvers, they’ve done really well,” Powell told Love Rugby League.
“Lee Radford‘s done a great job, the recruitment was excellent, it’s clear to see besides from some big name players who’ve done a good job for them but they’ve done well as a team.
“We go there rested and aggressive and that’s what weve got to do every week, find our own positives out of every situation and go and work our backsides off to get after every team.”
Powell knows Cas had a mountain to climb in the Super 8s to be in the running for Old Trafford in October.
He believes his side may have to win seven of their next seven fixtures.
“Probably seven, it’s got to be six out of seven,” Powell said.
“It is what it is, the only way you can do it is one at a time. You can only play one game each week and you just get on with it.
“I just think nothing but faith from us we can go and play.
“I was talking about us waiting to be shot at, I think we can grab hold of the gun a little bit and turn it around and say here we go let’s go and fire some bullets at the opposition and i think we can do that.
“We need to improve our defence, we’ve been second top scorers in the comp and the second worse defensive team so there are some great lines there in what we need to improve.
“There’s some good opportunity here to go and get stuck in to every team we play against week after week and see where it takes us.”