Jackson, who led the Addicks to the League One title last year, has suffered a stop-start campaign which was interrupted by a hamstring injury.
But the former Tottenham midfielder was in inspired form, leading from the front with two fine goals, as Charlton edged a nine-goal thriller 5-4 against Cardiff on Tuesday night.
"You look for that in a captain," said Powell.
"You look for that in all your players, but a lot of the time your captain is given the armband for a reason.
"I think he led by example in that respect with the two goals, and they were two well-taken goals as well."