Rafael, 24, arrived at Old Trafford in 2008 and has gone on to establish himself as the club's most senior right-back.
Speaking about his fellow Brazilian, 18-year-old Pereira has hailed the competitive streak that he has seen since he linked up with the senior squad, even in training.
"He doesn't like to lose. He is very competitive and always wants to win. He sets a really good example and is a really good pro," Pereira told the club's official website.
Pereira joined the Red Devils as a trainee from PSV Eindhoven in 2011.