SIR ALEX FERGUSON backed Wayne Rooney to fire 20 goals for Manchester United this season after his solitary first-half strike put paid to brave Birmingham at Old Trafford.<br /><br />The England striker got the champions up and running with a 34th minute winner from close range after seeing a header hit a post. His 99th goal for United capped a rather lethargic team display, but boss Ferguson was delighted with the winning start, while setting Rooney a goal target for the season to complement his new central striking role.<br /><br />“We had some good opportunities and played some good football and in general I am satisfied with the result,” the Scot said. “Is Rooney capable of 20 plus Premier League goals? He is capable of that without question. <br /><br />“You always need two or three of your strikers to get over the 20-goal mark. It has always been an advantage over the years for us and Wayne is capable of doing that.”<br /><br />Rooney was partnered up front by Dimitar Berbatov, but Ferguson insisted new signing Michael Owen will get his opportunity to shine in the coming weeks.<br /><br />Owen was only denied a debut goal by a fine save from Blues keeper Joe Hart and Ferguson added: “I started with Rooney and Berbatov today quite simply because they were at the club last season and were regular players and you’ve got to give them an opportunity. <br /><br />“Michael will get his chances. There is no question about that.”<br /><br />United fully deserved their victory but were grateful to keeper Ben Foster, who made an outstanding save to deny substitute Christian Benitez an almost certain equaliser late on.