The previous fixture at The Valley between the two was washed out back in August with Doncaster leading 3-1 at half time when it was called off.
"It was a deserved win, a brave, committed performance under some pressure," Powell is quoted as saying by BBC Sport.
"We knew it was our game in hand and we all knew what happened in the abandoned game - so we needed to make the most of it. We didn't perform in that game but that was a watershed moment, if you pardon the pun."
Three points saw the Addicks climb away from the drop zone and up four places to 17th.