Nani and Anderson joined United just over three years ago from Portuguese football.
Anderson has struggled to develop as expected while Nani has impressed from midway through last season.
“Everyone knows the quality that Anderson has,” he told United’s official website.
“He was unlucky with the knee injury that he suffered because he was just starting to play well and show us what we know he can do.
“We all know here that he is an amazing player.
“He is strong, he is a very clever player too and he can be a very important player in this team.
“He is a strong character too, which you need at this club. He’s not scared of anything. He’ll take the ball in any situation and he can be a top player for Manchester United.”
