MANCHESTER, August 17- Sir Alex Ferguson has challenged Wayne Rooney to beat last season's scoring tally of 20 goals after the United striker's finish was enough to earn Manchester United a 1-0 win over Birmingham City at Old Trafford on Sunday.Rooney’s 34th-minute finish was the difference as United shrugged of the absence of usual centre-backs Rio Ferdinand with a thigh complaint and Nemanja Vidic to a calf injury, to record an opening day win.
Ferguson said: "He took his goal well. The header was a good one and his following up for the rebound was quick and he reacted the right way.
"Hopefully that gets him on the road, after his goal last week, to a very significant total for us this season because it’s good if you can get two or three strikers that get you more than 20 goals. "He’s capable of that and we’re not asking the impossible of the boy."
United, who will be looking to win their fourth consecutive title this season, got off to a positive start as they seemed intent on proving the club still has attacking potential without Cristiano Ronaldo following his transfer to Real Madrid in June.
Dimitar Berbatov failed to make the most of a clear early chance inside the box as goalkeeper Joe Hart rushed out while Rooney also had a good opportunity from the rebound that was foiled by the committed Birmingham defence.
Hart had to again be on top form soon after as a wonderful curling Rooney effort from 25 yards was destined for the top corner until Hart acrobatically leapt to punch over the bar.
Birmingham, did try to break with the ball on occasion as James McFadden persevered down the left wing. But he rarely had a team-mate to choose from in the United box as the away side got most men behind the ball, a policy that worked until Rooney finally scored.
He watched his header from a Nani cross cannon onto the base of the post but fortunately for him, the ball bobbled back to him and he easily tapped over the line.
However, in a remarkable 60 seconds of play, Birmingham could then conceivably have been 2-1 up.
Firstly, Cameron Jerome unleashed a terrific 20-yard shot which just went wide courtesy of a slight Paul Scholes deflection and from the resulting corner, Patrice Evra was forced into a fine diving header off his own line to keep out Franck Queudrue’s effort.
The half should have been concluded with a second goal for United but Darren Fletcher somehow missed from point-blank range after solid work from Evra down the right wing.
After the interval Rooney saw a speculative 40-yard effort force Hart to go full stretch but the pace of the game was distinctly less intense than the first half.
Lee Carsley saved Birmingham when he cleared a Berbatov effort of the line with 20 minutes to go before the visitors also had a golden chance with 12 minutes remaining.
However, Christian Benitez could not beat Foster from close out as the United keeper made a stunning one handed save to divert the ball to safety.
Rooney had the a last chance to cap off a brilliant performance with another header as the end approached but he steered Ryan Giggs’ cross wide.
Birmingham manager Alex McLeish was satisfied with his side’s attempt and was impressed with how they did not shrink from the challenge of playing the champions at Old Trafford.
He said: "We have to use that as a confidence booster, we can go into the next game with the evidence of a great performance. I was very encouraged by it. The players should take enormous credit from that because they have to play in that cauldron without being intimidated."