Callum Harriott silenced the John Smith's Stadium with his first senior goal after just four minutes, and the Addicks held firm in defence to secure a morale-boosting away win.
Powell said afterwards: "It was hard-earned but I'm really pleased with the performance of the players.
"We had the perfect start. We countered well, we knew we would have to be on our mettle in the second half and we knew the pressure would come.
"Every player played their part but the centre-backs and the goalkeeper, they showed a real desire to keep the ball out of the net. It has been a long time coming, the clean sheet, I'm really pleased for all of them today."
On Harriott, he added: "He's a talent. He's someone I felt trained particularly well. He has done well with the under-21s, he catches the eye and he is a hard worker.
"He has talent. He came on as a sub last Saturday and made us a bit livelier. He started against Peterborough, had an assist and earned his chance for today.
"He did exceptionally well for the goal and worked hard for the team. It is exceptional for him to score a goal at this level.
"We have high hopes for him. You know we do produce players at our club and he's another one on the production line."