Haaland hit a Champions League hat-trick against Genk last night.
Solskjaer said of his former Molde protege: "It was nice watching the game last night, it was great watching him.
"Everyone's excited by his development."
On the Europa League, with United to meet Astana tomorrow, he added: "I won the group with Molde. You play different types of teams, different types of cultures. It is also a new experience for them. Two of the away games are AstroTurf so the home games will be important for us."