Ferguson admits problems in misfiring attack and injury-hit defence

A defeat, even a defeat at Burnley, where they had previously not conceded so much as a goal in 40 years, is not a crisis for Manchester United. However, Sir Alex Ferguson has acknowledged he faces problems with goalscoring and with injuries in defence.

Rio Ferdinand, who missed the opening two fixtures with a thigh injury, is more seriously hurt than first thought and will miss the next three weeks, which will almost certainly rule him out of England's World Cup qualifier against Croatia on 9 September. The United manager added Dimitar Berbatov and Michael Owen, who was taken off after 63 largely unimpressive minutes at Turf Moor on Wednesday, needed to find the net quickly.

"Against Birmingham and Burnley, we dominated two games of football but we would have liked to have scored more goals," said Ferguson, who was adamant yesterday there would be no further transfer activity from the champions. "Our goal difference last season was our poorest for 15 years. That was an issue last season and it will be an issue this year unless we step up to the mark, which I am confident we will do."

Both Berbatov and Owen have been plagued by poor form in front of goal. The Bulgarian has found the net once since March, while Owen last scored 20 competitive games ago, on 10 January. Ferguson acknowledged that, in contrast to Wayne Rooney, Berbatov's lack of obvious aggression had, perhaps unfairly, counted against him with the Old Trafford crowd.

"Strikers always feel as if scoring is the most important thing," said Ferguson, a one-time centre-forward. "That is the case with Dimitar. He had a couple of attempts at Burnley and was a bit unlucky when he curled the ball just over the bar. He had a header cleared off the line against Birmingham. He has a languid style and maybe that is the thing that people hold against him – his style of play rather than the actual affect he has on the game. But I am happy with his performance; he is a very, very good player.

"Michael is exactly the same as Dimitar. He could do with a goal. He had two opportunities on Wednesday and should have scored both of them. He knows that. He was unlucky. But there is no question that his movement and positional play in the last third is very, very good. We are just waiting on the goal that will set him off."

Cristiano Ronaldo's departure for Real Madrid left many questions, chief among them the identity of United's penalty-taker. Throughout pre-season, Ferguson insisted that this would be decided on a game-by-game basis, and defended the choice of Michael Carrick to take the spot-kick at Burnley which was saved by Brian Jensen. "Michael Carrick said himself last week he felt confident taking penalty-kicks," Ferguson argued. "He asked to take it. He had never missed a penalty in all our shoot-outs over the last few years. He was a confident choice."

Manchester United's defensive problems leave Ferguson few choices as he prepares for tomorrow's encounter at Wigan, a venue where United have never failed to win. Despite the fact that he has not played at all in pre-season, Nemanja Vidic will go straight into the back four this afternoon.