The Seagulls hit the woodwork twice in stoppage time but Charlton held out for a valuable point in their bid to steer clear of relegation trouble.
Powell was delighted with the way the Addicks followed up last Saturday's 3-2 home win over Bolton, and said: "I'm really pleased. It was a great point for us.
"Brighton is a tough place to come and I knew we would have our hands full, but I felt we had our tactics right.
"Our shape was right, the point and a clean sheet is really pleasing for us following our win last Saturday.
"Come the end of the season this point could make a difference. Going into the game we have taken a point and a clean sheet. In the end we could have even nicked it and Ben Hamer also made a crucial save at the death."
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