In my opinion one of the best ALL-TIME boxers who fought on the inside was Roberto Duran. He was aggressive, he put his punches together well, but he had exceptional defense while being aggressive. It's amazing how just slight head movement, rolling with punches, etc would put him in perfect position to counter and would keep him from getting KO'd or knocked down. I don't know if he was just brilliant at timing his opponents or if he read their movements or both, but he could work in the pocket extremely well.