Guidolin branded the display the worst during his time in charge of Udinese.
"This was the worst home performance of my time together with Udinese. We played very badly," the Coach told Sky Sport Italia.
"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.
"We didn't give up till the end and showed some pride in the second half, which can be the only positive from this game.
"There are no excuses. We played badly and now have to get back to work in order to understand what happened. 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."
For breaking stories and all the great banter like us on Facebook: facebook.com/tribalfootball