The Bluebirds secured promotion to the Premier League but were made to work for their point as the Addicks pushed them all the way at the Cardiff City Stadium.
Powell told reporters: "We had good spells. I said to the players we had our moments, we definitely played our part. It keeps our unbeaten run going and it is another clean sheet.
"We showed a lot of character and we've taken four points off Cardiff so we are not that far off. I am very pleased with the display."
Charlton all but secured their place in the Championship next season, although they are still not mathematically safe from relegation.