Spong has matured so much, hasn't let young success get to his head, if he did he's overcome it. He always had the skill, but experience is a huge factor. The boy is embracing his experience and staying active, realizes fighting is his trade, he's a threat to any professional fighter on the planet.
Anyone he lost to in the past would probably not go the distance with him now, as Corbett discovered. Spong has turned his talent into his lifestyle and that is scary.