First half goals from Cristiano Ronaldo and Carlos Tevez against Manchester City at Old Trafford strengthened United's grip on the Premier League title.
The Reds were dominant in the first half and made the breakthrough in the 18th minute when Stephen Ireland brought down Dimitar Berbatov just outside the box.
Ronaldo stepped up and blasted a low free kick that, with the help of a slight deflection, beat Shay Given into the right corner of the net.
Tevez hit the post shortly after as the home team pushed for a second goal. United continued to boss affairs and deservedly doubled their lead before halftime.
Berbatov took down a long ball and squared it to Tevez, who moved to his right and whipped a spinning shot past Given, going in off the post.
The Argentinean chose to celebrate near his manager, placing his hands on his ears as if to say he was open to listening to offers for him to stay.
The Red Devils started the second period sluggishly and City had their best opportunity to get back into the game when Robinho was put through on goal, but the Brazilian blazed his shot wide.
If the reaction of Tevez to scoring was provocative, then Ronaldo's behavior on being substituted in the 59th was utterly childish.
The World Player of the Year petulantly flung his training top to the ground before taking his seat in the dugout, shaking his head and sulking only the way the Manchester United number 7 can.
Petrov came into the game for City and tested Van Der Sar late in the game, but United were in cruise control and came close to adding a third Scholes, Rooney and Tevez, whose headed effort hit the post. .
Another three points for United. There are three games left and they only need four points to secure an eighteenth League title.