The Viola lost 2-1, having gone into the game on the back of victory over AS Roma.
"We are very bitter, as we were unable to bring home the result, even managing to lose," said the Coach.
"The goals came from mistakes, which were small but consecutive, and that is not good enough for a team that wants to aim high.
"We had controlled the game. We always want to give our best, but we have to understand whether this really is our best."