Johnnie Jackson's bobbling strike and Scott Wagstaff's predatory effort gave Charlton a two-goal lead at half-time, and Blackpool could only get a consolation in second-half stoppage time.
"It's Saturday and we've won a game," Powell said.
"It's been a long time coming. I've been saying if we can improve our home form just a little bit we could have a better position in the league.
"The fans come to the Valley and want to see their team do well to set up their week, and we've done that against a decent Blackpool team.
"They've had some upheaval with their manager going but football is football, they will always come and play and it was up to us to combat that and the players worked ever so hard for the result."