De Ketelaare is fulfilling his potential this season after struggling last term at Milan.
He told Sportweek: "At Atalanta I found myself physically and mentally.
"Some 'clicks' went off in my head and I started again. Compared to Milan I play in my true role, as a forward.
"I don't know what it will happen in the future, but now I feel like I'm there. Today I feel like I'm a serene, confident, proud player.
"My work isn't finished, but I'm on the right path."