Hato opened the scoring on Saturday night, so becoming the first Chelsea player to net under new manager Liam Rosenior.
He told Chelsea's website afterwards: "To be honest, I was a little bit surprised when it went in so that’s why I didn’t really celebrate too much!
"I think it was a good hit and I’m just so happy to score for this great club. The ball bounced and landed just in front of me, it was sat up nicely and thankfully it’s flown into the top corner.
"I enjoyed the game, it was a real cup tie and the role I played allowed me to get forward a lot, into pockets of space in and around the box. I enjoy being able to help offensively as well as defensively. It’s a new role for me, because during my time at Ajax I only ever played as a defender.
"(Enzo) Maresca wanted me to invert and join in attacks previously, and now the new manager has asked the same of me. It’s a new role but one I’m happy to do and I’m really enjoying the first few days under the gaffer."
Hato added: "We knew it would be a difficult game. We expected Charlton to be physical, to play a lot of long balls and for there to be a lot of duels all over the pitch. But we knew if we matched the energy, then our quality should come through, and I think that showed in the end.
"The manager made it clear to us coming into this game that we would need to show a lot of fight. He demanded that intensity of us and it worked, winning 5-1 is very good."