The Brazilian, now with Atletico Mineiro, told the Daily Mail: "No, because I have played for some of the biggest teams in the world and won everything. The only regret is not playing more seasons with Lionel Messi.
"He is my good friend. I could see even at a young age he was going to be the best. It was exciting to see this kid who could do things most players can only dream of.
"If Manchester United had signed me they would have won more European Cups!"