Antonio Valencia has backed his Manchester United teammate Rafael da Silva to become "one of the best right-backs in the world".
Brazilian defender Rafael has earned numerous plaudits for his performances this season as United appear to have ended their search for a successor to Gary Neville.
The latest person to praise his development is Valencia, who has tipped the 22-year-old to become one of the best full-backs around.
"It's incredible how much he's improved. I've seen a big improvement in his level of concentration," said the Ecuadorian winger.
"If he continues, it won't be long before he's one of the best right-backs in the world."
Rafael has made 22 Premier League appearances this campaign, scoring three goals in the process.
