Wayne Rooney scored his first goal since March as Manchester United cruised to victory to remain two points behind Premier League leaders Chelsea. Rooney converted a 33rd-minute penalty to end a 13-game drought after Jonathan Spector fouled Ryan Giggs. Nani's cool finish from Rooney's neat pass made it 2-0 while Kieron Dyer hit the post for winless West Ham. Dimitar Berbatov capped a fine performance by volleying past Robert Green from Nani's chipped cross. West Ham's defeat left them rooted to the foot of the table and without a point while Manchester United remain third, level with Arsenal. The Hammers' task was always going to be difficult, with Avram Grant's side without an away win in the league since the first game of last season. But Manchester United, who had won 11 of their previous 12 league games at Old Trafford, started sluggishly with Rooney in particular struggling for form. However, as the half wore on, United's veteran midfield duo of Paul Scholes and Giggs started to impose themselves on the game with Nani - who replaced Antonio Valencia in the starting line-up - also finding space on the right. The Portuguese winger came closest to breaking the deadlock early on when his fierce 25-yard shot was palmed onto the crossbar by Green. At the other end Dyer proved a useful outlet for the Hammers, while striker Carlton Cole was only denied a shot on goal by a last-ditch tackle from the superb Nemanja Vidic. Dyer found the side-netting for the Hammers but Manchester United continued to press for an opening goal and just after the half-hour it came - albeit from the penalty spot. Scholes found Giggs on the left with trademark vision, and after turning Spector inside out, the Welshman was eventually brought down by the Hammers defender. It gave Rooney an opportunity to score for the first time since 30 March and the England striker made no mistake, finding the bottom of the net with a low penalty that sent Green the wrong way and brought to an end the longest barren spell of his career. Soon after, Darren Fletcher saw his curling 25-yard drive superbly tipped round the post by Green as the Red Devils continued to press. The hosts should have gone into the break 2-0 up but Nani wasted a glorious opportunity on the stroke of half-time, lifting the ball over Green but also over the bar from close range after a stunning clipped pass from Giggs. However, Nani made amends for his miss just after the break, lashing the ball home left-footed from the edge of the area after cutting inside his marker following Rooney's weighted pass. Rooney himself was denied by a last-ditch Danny Gabbidon tackle before a fine passing move from West Ham saw Dyer crash a fierce shot against the outside of the post. Scholes then tested Green from the edge of the area after good link-up play from Berbatov as the game started to turn into a procession for the hosts. United soon increased their lead and having turned provider for Scholes, it was Berbatov's turn to be on the receiving end with Nani's clipped pass to the back post acrobatically volleyed home by the Bulgarian. Cole and Vidic continued their personal duel with the Serbian defender again coming out on top as another last-ditch tackle denied the England striker a clear sight on goal. Hammers striker Fredric Piquionne tested keeper Edwin van der Sar late on but the Dutchman was equal to the effort as Manchester United held on to keep their second clean sheet of the season. Credit: BBC