The Nerazzurri failed to make up ground on Fiorentina and Napoli in the table, as their hopes of qualifying for next season's Champions League took a blow.
"I must congratulate the Sardi because they played well, they made very courageous decisions," he told Rai Radio. "Against Fiorentina we went ahead but we couldn't do that today. Getting in front is important.
"It was a particular game that we drew, we created a lot of chances but we couldn't take them. Unfortunately today we handled a few situations badly.
"We are all a bit annoyed because today we did everything we could to bring the three points home."
Inter Milan return to Serie A action next Saturday, when they face Roma at the Stadio Olimpico in Rome.