The 35-year-old winger scored his 97th Premiership goal for United in the 62nd minute to hand his team the away win.
The win brought The Red Devils back to the league summit with 56 points, two ahead of second-placed Liverpool.
West Ham started the game on top, and threatened Edwin van der Saar with two early efforts through Carlton Cole and Lucas Neill. The Dutchman did well to keep the score level.
On 21 minutes, Dimitar Berbatov through that opened the score line, before the goal was disallowed for an earlier foul in the West Ham box.
The hosts’ keeper Robert Green was called into action in when Ryan Giggs’ ball was met with a first time hit from Paul Scholes in the 31st minute.
In the second half, United looked more likely to score first. And after 15 minutes of controlling possession, Ryan Giggs took a well-earned lead for Alex Fergsuon’s men.
The Welsh received Scholes’ pass and cut inside from the left, before hitting a right-footed shot past Green in the Hammers’ goal.
West Ham pushed for an equalizer, but United were more than happy to sit back and end the game with the 1-0 win.
Watch the game's goal: