The French striker, who played for the Foxes before joining the Addicks two years ago, was inspirational as the hosts recorded their first win of the Championship campaign.
"When Yann plays like he did here then not many strikers are better than him," PA quotes Powell as saying.
"I'm going to tell him there are 23 other teams called Leicester. He has now played against them three times and scores three times. It is pleasing for him as he had rough time there.
"He is good in the air, on the ground and he sees other things people don't. I was there with him as a coach so I knew he was a good player and that's why I brought him in. It was a good day for him and us."
Kermorgant scored just one goal in 25 appearances for Leicester.