Flamengo's vice-president, Kleber Leite, confirmed United had made an approach yesterday while talking to local reporters at the Maracana.
United had asked about Renato's availability next month, but Leite insists the youngster wants to stay with Fla.
Indeed, earlier this week, Renato said: "It is nice to know Europe clubs are following me. But I want to stay with Flamengo and make history with this club. I want to be as well known as Andrade and Adilo at Flamengo."
Renato is tied to Fla until 2010 and his contract carries a £20 million buyout clause.