Dimitar Berbatov's double allowed Manchester United to strengthen its grip on the Premier League lead with a convincing 2-0 victory on Sunday over a depleted Sunderland. The Bulgaria striker nodded Wayne Rooney's lofted cross into the net after five minutes and also hit the post during a first-half onslaught. Berbatov was on target again -- slightly fortuitously -- when a 57th-minute strike deflected off Sunderland defender Anton Ferdinand past goalkeeper Craig Gordon. Unbeaten in the league all season, United has a two-point lead -- and two games in hand -- over crosstown rival Manchester City, which won 3-1 at Newcastle. Arsenal is five points behind United in third having played the same number of matches as the leaders. 