Former Real Madrid midfielder Kaka has praised Cristiano Ronaldo’s ability to keep bettering himself and winning important trophies.Ronaldo, 31, ended last season with a third Champions League title and a first major international honour as he helped Portugal win the European Championship and is favourite to win a fourth Ballon d’Or (previously called the World Player of the Year) .And Kaka reckons it is unlikely to be the last silverware of his career, reports ESPNFC.‘It’s incredible, he shows every year that he can beat himself,’ he told Omnisport. ‘Every year he has motivation to keep going, to keep scoring and be the best player in the world.‘Sometimes when you have won a lot of things in your career, it is normal to slow down a little bit so maybe the motivation in your mind and mentality is not easy.‘But he is so incredible like [Lionel] Messi because these guys have won everything they could and they still want to win, they still want to be the best. It’s incredible.’