The Zebrette went behind at the San Siro, but finished 2-1 winners on Sunday.
An under pressure Chivu remarked afterwards: "We need to maintain the motivation and enthusiasm we had a few days ago. We were a bit fussy, not carrying the ball and not looking for superiority. All this despite the lead.
"The penalty incident damaged us a bit mentally. We lost our composure and had a few second balls, along with a few duels. We knew Udinese was a physical team. In the second half, we made a few different runs, but not enough to take it home.
"Today we tried everything we could to have players accustomed to playing in the box, but unfortunately we couldn't find them. This construction site can't remain open for long, even though it's only matchday two. I take responsibility because perhaps it was also my fault that I wasn't able to convey such calm.
"The team has done some good things in recent years, and I'd just like to address a few flaws, including our search for play. We need to be more concrete and pragmatic, especially when it comes to our opponents. We need to learn to do things that are more appropriate for our opponents."