The 17 year-old is currently playing on-loan with Flamengo ahead of joining Real for preseason later this year. He is currently enduring controversy in Brazil after being sent off against Botafogo this week.
Diego, who has played with Vinicius at Fla, told AS: "Vinícius is a sensational boy, simple and good-natured, but he's having a difficult time.
"We must understand the mistakes he makes. His style of play, more daring and cheerful, attracts attention.
"He did not ask for all this attention, but to be signed by Real Madrid, with these numbers, it gives hope for things he cannot do sometimes."