The Inter defender has reserved special praise for his team-mate's attitude, professionalism, and is convinced that his side can challenge Juventus for the Scudetto title
The 39-year-old has been at the club for 17 years, and the Italy defender has been impressed by his team-mate's attitude and leadership.
"Apart from the physical and athletic side, which is impressive, the fact is that I've never seen a day, I say a day, in which he is not cheerful, captivating and serene," he told Repubblica.
"He is always positive, has a word for everybody and is an example.
"I remember in 2011 when in 4 days, with Leonardo, we lost the derby 3-0 and then 5-2 at home against Schalke in the Champions League.
"The next day Zanetti arrived at Pinetina with a serene look, and spoke to us in the way a captain must do."
Inter currently lie fourth in the table, nine points adrift of league leaders Juventus, but the Italy defender remains convinced his team can still trouble the Bianconeri.
"I am convinced that Inter can still fight for the title, and that Juve is not necessarily the best. We truly believe in the comeback."