Under the tutelage of Zinedine Zidane, Madrid became the first side to successfully defend the European crown in its current format in 2017.
Los Blancos also won La Liga last term, but domestic success this season has failed to materialise – Madrid are 15 points behind league leaders Barcelona and were beaten by Leganes in the Copa del Rey.
Despite their troubles at home, Madrid have continued to flourish in the Champions League and face Juventus over two legs next month in the last eight.
"It's possible they'll win it again because of the greatness of the club, it's the best in the world," the former Brazil international told Omnisport, speaking courtesy of Hublot.
"We [Madrid] have improved a lot now so we are in the right way."
And even the possibility of facing Lionel Messi and Barcelona does not worry the three-time Champions League winner.
He added: "A team who has 12 Champions Leagues should not [have] any problem facing a team who has five."
Madrid's domestic woes have brought pressure on the shoulders of Zidane, however, his former team-mate has faith in the head coach.
"He [Zidane] is proving he is the best manager in the world," said Roberto Carlos. "And as a player, he was the best player in the world, also he won the World Cup and the Champions League.
"He left the pitch as a great player and professional, and now he is a great manager winning everything."