كتب : Hatem Maher
United are in charge of the league table with 81 points, three ahead of second-placed Chelsea, who have slim hopes of clinching the title.
Both sides meet next weekend. If United avoid defeat at Stamford Bridge, they will likely win the Premiership for the second successive season.
The hosts went ahead after 21 minutes when Paraguayan striker Roque Santa Cruz capitalized on a defensive mix-up to fire home.
Nemanja Vidic and Rio Ferdinand accidentally collided with each other to allow Santa Cruz shoot past stand-in keeper Tomasz Kuszczak.
Some heroic saves from American guardian Brad Friedel prevented United from claiming a much-needed equalizer.
Portuguese winger Cristiano Ronaldo also saw a low bullet rattle the post three minutes past the hour mark.
United's pressure finally paid off with two minutes remaining when Tevez rose unmarked to head Paul Scholes' flick-on past Friedel from six yards.