A late Mirko Vucinic strike gave the visitors their win.
"There is no such thing as an anti-Inter this season," insisted Ranieri. "There is Inter and that's it. They are too strong and cannot be caught.
"We showed that we know how to survive pressure and emerge unscathed. Julio Sergio was simply extraordinary.
"Fiorentina played very well and we were a little lucky, so that always helps."