Having started brightly the visitors failed to take a few early chances and were subsequently punished by the champions who were in second gear for much of the contest
A fairly one-sided affair was dominated by the champions, who were wasteful for much of the game.
A moment of pure opportunism and a coolly taken penalty from Wayne Rooney secured all three points for Alex Ferguson’s side, as the visitors were thwarted by David de Gea on the few occasions they managed to break out of their own half.
Despite an early spell of dominance from the home side, it was Roy Hodgon’s men who created the first clear-cut opportunity.
After Liam Ridgewell had done well to reach the byline down the United left, the defender cut the ball back to the unmarked Keith Andrews who somehow contrived to prod wide from six yards out.
United responded well to the early warning from the visitors, with both Welbeck and Ashley Young coming close before Andrews stung the palms of the ever-improving de Gea from a freekick.
The champions enjoyed nearly 70 percent possession in the opening half hour and it wasn’t long before their dominance was transformed into a half-time lead.
Following good work from Young, Javier Hernandez found himself with time on the edge of the Albion area. The Mexican cut back onto his left and curled an effort towards goal, and with the West Brom defenders stood statuesque, Rooney produced a superb piece of opportunism to sneak ahead of Ben Foster and prod hid side into the lead.
The champions started the second half in much the same vein and were a width of the post away from doubling their lead.
Some good interplay between Hernandez and the impressive Rooney resulted in the Mexican producing a stunning effort on the edge of the area, but the United man’s luck was out as it fired back off the woodwork with Foster beaten all ends up.
There was to be no rest bite for the Baggies defense as the United onslaught continued, with Welbeck firing inexplicably wide with just Foster to beat.
However, any chances of an Albion fightback were relinquished as the visitors pressed the self-destruct button shortly after the hour mark.
First of all, Jonas Olsson crashed into the back Hernandez who was just too fast for the Swedish defender, and having been booked just 15 minutes earlier, the Albion man was heading for an early bath.
The Baggies misery was complete just five minutes later as Young tumbled in the box under pressure from Andrews, Lee Probert showing no hesitation in pointing to the spot.
Rooney stepped up and coolly slotted home his 20th league goal of the season, sending Foster the wrong way.
Roy Hodgson introduced the energetic Shane Long with 20 minutes to go, and the Irishman almost made an immediate impact, forcing de Gea into a smart save at his front post.
The fightback never really looked like materializing from Roy Hodson’s men, as United saw out a comfortable victory, moving to the top of the table at the expense of their Manchester rivals, West Brom stay in 13th.Follow GOAL.COM USA on