Inter are back in the hunt for the title thanks to Leonardo's influence.
Milito told Uefa.com, "We had a strange start to the season with a lot of injuries, but now things are getting better.
"When Leonardo arrived here, he gave us confidence and I think that's crucial. Now that the coach has a lot of players at his disposal and the team is solid, we finally feel strong again.
"This is one of the things that have changed in the last few months. Winning the FIFA Club World Cup also gave us belief."