"I certainly feel that my time here has been a success," the Denmark international told Jyllands-Posten.
"I joined as a small fish in a big pond and you have to be very strong not to get lost in that environment.
"I've had spells where I've been first-choice goalkeeper, which far exceeded my expectations, but that does not mean I am satisfied.
"Personally, I feel that I still haven't achieved my dream at United.
"I want to be a regular in the team, playing every time and delivering in the big games. That's my objective, and I've only partially fulfilled that."