Former Manchester United and Arsenal defender Viv Anderson says Rafael will learn from his red card against Bayern Munich.
Anderson has no doubts the United fullback will go on to have a huge career.
He told givemefootball.com: "It was impudence of youth, if you like, but we have all been through that. I'm sure I did it when I was younger, but I was playing for Nottingham Forest, not Manchester United at the time. He is learning on a bigger stage than I had."
However, the former England international is confident Rafael will learn from his misfortune and go on to become a big United star.
"I see enough in Rafael to believe he will be successful," added Anderson.
"He is a tough little lad and is very good going forward. He has to learn positional sense, but that comes with playing. In another two years' time he will be the finished article and he will be a top player."