London - Manchester United's Brazilian midfielder Anderson has signed a new four-and-a-half year contract, the Premier League leaders said on Wednesday.
The 22-year-old former Porto player returned in September after suffering a serious knee ligament injury last season.
"We are delighted he has signed a new contract," Ferguson told United's website (www.manutd.com).
"Anderson has developed tremendously since joining us and he has fantastic potential at only 22; he is going to be a really top player."
Anderson has made 110 appearances for United since joining in 2007.
He initially struggled to make an impact at Old Trafford, but scored an important goal in the Champions League against Valencia this month and has recently shown signs of fulfilling his potential.