The 23-year-old has failed to kick on at United since his Â£56m arrival with a goal against Liverpool on his debut four years ago. But Pires reckons he can come good.
â€œHe's a great player, very talented, with great ability with the ball," he said.
â€œPremier League, Manchester United, it's a very, very difficult combination for a young player.
â€œWe know they earn a lot of money and I'm very happy for them but the pressure also is huge. He's still young, but it's not easy."