The Addicks remain firmly in play-off contention, but Powell was upset not to have cut the points gap on the automatic-promotion places.
Defeat ended the Londoners' four-game winning running, and Powell said: "It's disappointing as we had the joy of four wins, I'm realistic and know it will happen.
"I want to win them all, but this has come to an end in this game. We didn't start well, but I got a response from them and losing here - it's one of the games we wanted to win to impress on the top two.
"I can never fault their efforts and endeavour but at crucial times we didn't show the right football nous, or pick the right pass or show the quality.
"But these things happens and I will learn from it and see how they react to a defeat. It's a learning curve for anyone."
Source: PA
Source: PA