Materazzi left in the summer when his contract was terminated by mutual consent, as he was told he no longer had much chance of playing under sacked boss Gian Piero Gasperini.
"The new Coach got off to a strong start, as the victory in Bologna could be crucial to regain confidence," Materazzi told Ria Novosti in Russia.
"Ranieri is a good Coach and with Inter, one of the best sides in the world, he has the chance to achieve great things here.
"Inter always played with a 4-4-2 or a 4-3-1-2. Ranieri understood that and the team immediately gave a strong response. It's only normal they went back to winning ways."