The pair were able to celebrate the LaLiga title last week.
"My brother Sergio is a phenomenon," Modric told Sportske Novosti. "And I'm not just saying that because in eight years we've created a really special relationship, we hang out as families, go on holiday together, or because we've had fantastic footballing experiences and successes together.
"Ramos is a 34-year-old rock, a top-level competitor, and when you watch him working on himself, it's clear how dedicated he is and how hungry he is for success. He's a team leader and the best defender in the world."