Cosmi called on his players to begin supporting better centre-forward Cristiano Lucarelli.
He said: "Lucarelli can't create an entire front line by himself. The two trequartisti were out of sorts and we made little impact with our shots. There were also more mistakes in defence than we had seen recently.
"We are going to have a tough campaign all the way through, but hopefully in January make some changes to cover the areas where we have problems."