Frank de Boer admits Inter Milan "have a lot of work to do" after an opening day defeat at Chievo Verona.

Valter Birsa struck twice for the 2-0 Chievo win.

“We are very disappointed by the result and have a lot of work to do," De Boer told Mediaset Premium.

“I am confident we will improve both in terms of the football and physically. Next week we will try to do better.

“I chose this system because we are not in the best shape. 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."