The Italian striker has had a controversial time in England since he moved to City a year ago but Giggs, who was speaking at the 2011 Golden Foot Awards, told the audience that he is still a very gifted footballer.
"He is very good, but also a little strange," he said.
"In England all but the City fans hate him. But trust me, he is very talented."
United go into Sunday's match at Old Trafford two points behind their local rivals.