The Zebrette slipped to their second successive home loss at the hands of Inter, who controlled the game throughout and claimed three points thanks to strikes from Rodrigo Palacio, Andrea Ranocchia and Ricky Alvarez.
He told Sky Sport Italia: "This was the worst home performance of my time together with Udinese. We played very badly. I'll have to analyse what happened, but we'd never conceded from set plays like that.
"We played badly, deserved to lose and it is a difficult defeat to swallow, with all due respect for Inter. We were absent today. There are no excuses.
"Above all, we must all realise this is a different season to previous years. We need the bit between the teeth and fight for every point. We have some problems to resolve, but those are in-house."
Udinese have now lost six of their first 11 matches of the campaign, leaving themselves 10th in Serie A.