Manchester United defender Nemanja Vidic says his scratchy form this season is down to niggling injuries.

He has only just returned from a calf strain that kept him out for three weeks and a pre-season knee injury saw him consigned to the sidelines for the opening three games.

"I am not happy because I have had a lot of injuries," he said.

"All the time I feel something. That worries me. But I don't have a problem with my form and at the moment I am 100%."

Nevertheless, the axis between Rio Ferdinand and Vidic has been in operation on only four occasions in the Premier League this season.

The only time United failed to collect maximum points was at Liverpool, which probably explains why United have looked defensively slack at times this term.

"We need to get back to keeping clean sheets," he said.

"It is very important for the team when you don't lose goals. When you have stability at the back it is easier for the forwards and midfield players.

"With the quality players we have we can always score. This year, not just Manchester United, all teams have lost more goals than last season.

"But we need to improve and I hope we will do better in the few games."