United’s lack of goals has worried manager Sir Alex Ferguson this season.
The Red Devils has scored just four goals in their last six league games.
“We are having a lot of 1-0 wins but sometimes it is because we are missing a lot of chances,” he told the Daily Mail.
“You lose your concentration sometimes and the teams we are facing are defending very well. Middlesbrough were very good on Monday night.
“It would be nice to get a second or third goal but 1-0 is enough. You still get the three points.
“We are not really worried about it, but maybe we must work on our concentration in the final third of the field.
“The boss tells us all the time not to lose our concentration because it will be very important in the crucial games coming up.
“So we will keep working on that and as long as we keep making chances, hopefully the goals will come.”
