Frank de Boer said Inter must improve after his new side were beaten 2-0 at Chievo in their opening Serie A match on Sunday.
The former Ajax coach has only been in charge at San Siro for two weeks, and he could not inspire his players to victory in their first game of the campaign following Valter Birsa's brace.
And, speaking after the defeat, De Boer admitted he and his team have work to do in order to make this season a success.
"We are very disappointed by the result and have a lot of work to do," he told Mediaset Premium.
"I am confident we will improve, both in terms of the football and physically. Next week we will to try to do better."
De Boer also added that he had tailored his line-up with Inter's pre-season struggles in mind.
"I chose this system because we are not in the best shape," he continued.
"We played three at the back based on our condition and the way Chievo play.
"We conceded a goal in the most difficult moments, the game went because we are not at our best physically. When you concede that type of goal, it's difficult, but this is football.
"I think fitness levels influenced our tempo and that is why I decided to play with three.
"We had only one friendly match together, so I haven't had much time to improve these aspects."