Tony Smith's troops ran in no fewer than eight tries at the Halliwell Jones Stadium to move fourth in the Super League.
Powell made six changes with one eye on the upcoming Challenge Cup final with Leeds Rhinos, and the 49-year-old says that he could only stomach last night's defeat if a "bigger prize" comes out of it.
"It's a little bit disappointing," he told Sky Sports News. "We were a bit unlucky with the scoreline, I don't think that was a fair reflection.
"We put a team out there that I thought should have competed a little bit better. I think we had to be sensible with team selection.
"I never like losing, to be honest, particularly not in that manner, but sometimes you've got to cop a whack on the chin to get the bigger prize."
Castleford face Leeds at Wembley next Saturday.