Former Inter Milan midfielder Borja Valero says they looked tired in defeat to Bologna.
Riccardo Orsolini struck for Bologna's 1-0 win.
Valero said, "The Champions League objective is difficult, they will have to fight until the end with four other teams.
“I think Inter are a bit tired at a psycho-physical level, we saw it immediately: Bologna entered the match much better.
“Inter are not used to us not creating dangers like today: we saw few shots, Skorupski saved little. Today we could really see a physical and mental drop: with Porto they spent a lot, it wasn't easy to come to Bologna and it showed.
“You can't say that the Champions League is at risk, they are still second: they are in the right position, but these games make the difference, with a win you put some distance between the others."