United overcame Aston Villa in a key game during the successful 2009 title campaign with a dramatic late winner by Federico Macheda.
As Sir Alex's side prepare to face the Midlanders again this evening, with three points guaranteeing a 13th title for the boss, we thought it was an opportune moment to look back at the pulsating encounter four years ago.
With Liverpool applying pressure at the top of the table, the Reds were heading for a costly defeat until Cristiano Ronaldo bagged his second goal of the game to equalise. However, the late sting in the tail was provided by 17-year-old debutant Macheda in injury time.
The Roman came off the bench to curl a beautiful winner beyond Brad Friedel's outstretched left hand to spark chaotic scenes at Old Trafford.