United took the lead through Dimitar Berbatov after a one-two with Michael Carrick put the Bulgarian in space on the right, and he made the finish look easy as he placed the ball past Scott Carson.

The Baggies suffered a massive blow when their captain Paul Robinson was sent off with a straight red card after a reckless two-footed challenge on Park Ji Sung. However, many felt referee Rob Styles' decision was a harsh one as there was no apparent malice in the tackle.

A dreadful mistake by Carson gifted the Red Devils with their second goal as a free-kick from Ryan Giggs was collected by the goalkeeper, then dropped at the feet of Carlos Tevez who took the chance with glee.

Nemanja Vidic ensured that United would be three points clear of Liverpool at the final whistle when he scored the third goal of the match. Giggs swung in a corner from the right and the Serbian glanced a header into the hapless hosts' net.

However, the Premier League leaders were not done yet as they increased the home fans' humiliation by scoring two more before the end.

Ronaldo was the man who emphasized the victory by netting twice within eight minutes. The first saw the Portugal international run onto a pin-point Giggs cross and his brace was secured when he combined with Berbatov and slid the ball between Carson's legs from close range.