United are now seven points clear with just two games left to play.
Boss Sir Alex Ferguson said: “It’s a fantastic day for the club and fans.
“There was an emphasis on the league and the key was our good start. Once we made that, we never lost it.”
Ferguson added: “The Premier League is such a competitive league and the focus and the pressure on the big clubs makes it a focus for us.
“I used to have an obsession of winning in Europe but the Premiership has become a priority.”
Ferguson has led Manchester United to nine Premiership titles.