One side was a history dominated by the defending champion, should have won by a bigger margin if not for their wastefulness in front of goal.
A moment of opportunism and a fine fresh Wayne Rooney secured the three points for the Reds, as visitors were hampered by David de Gea on those occasions that made it out of their environment.
Sir Alex has made four changes to the side was retired at home to Athletic Bilbao in midweek with Rio Ferdinand, Michael Carrick, Paul Scholes and Danny Welbeck all the current recovery began.
For tourists there are two sides to switch to a victory over Chelsea at the weekend, with Gabriel Tamas and Chris Brunt started in place of Jerome Thomas and Steven Reid was injured.
Despite a spell of local computer domain, Roy Hodgon the man who created the first clear chance.
After Liam Ridgewell had a good left defender sent the ball back to Keith Andrews scored forcing people from six meters wide, where it is probably easier to test De Gea.
United responded well to early warning, both Welbeck and Ashley Young to close before cutting the palms Andrews constantly improving Gea with a free throw.
Champions receive almost 70% ownership in the opening half hour and it was not long before their lead at half time of delivery.
After a good work of the young, Javier Hernandez was found over time on the edge of the area of West Brom. Mexico cuts on his left side and curled an effort towards goal, Rooney to produce an excellent piece of opportunism to sneak ahead of Ben Foster and women in their role, with the imposition of defense around.
The United started the second half in the same direction and width of the paper to duplicate them.
Awesome game between Hernandez and Rooney for the results of play of a circle of 25-yard effort with Foster beaten all ends.
There should be no rest bite to protect bags as the home team continued to attack, shot somehow Welbeck with Foster to beat.
However, any possibility of a return of the struggle of West Brom the visitors left the self-destruct button just after the hour mark.
First, Jonas Olsson has his marching orders after receiving a second yellow card for Hernandez land barges, before the area fell under pressure from Andrews to take a penalty.
Rooney steps and objective fresh grooves 20 of the championship season, Promotion sending the wrong way.
Despite the introduction of an energy of Shane Long, forced De Gea into circulation within a few minutes trying to finish, Hodgson's men never looked back in the game.
With three points in the bag, United moved a point clear at the top of the table Manchester, at the expense of their rivals of the season with 10 games remaining.