"I feel sorry for Milan, but I remembered them as being better than that. I didn't expect to see them play like that," the 26-year-old midfielder gloated.
"But this is a very important win for us which we wanted so much and really fought for."
Celtic's last-gasp winner was sadly overshadowed by one fan who ran on to the pitch and slapped Dida in the face, prompting a UEFA investigation.
"It isn't a nice thing to see," admitted Donati. "But I don't think that it would be right to punish such a great set of fans for one man's stupid gesture."