Manchester United midfielder Shinji Kagawa has insisted that injuries have prevented him from displaying his full ability at Old Trafford.

Kagawa left Borussia Dortmund to join United during the summer after impressing in the Bundesliga but the Japanese playmaker believes that a knee injury has stopped him from making a better impression at the Premier League leaders.

He told the club's official website: "I'm not satisfied so far, but then I am always very critical of my own performances. Even worse, though, I got injured.

"I had to go through the frustrations that come with getting injured in my first season with the team. Now I'm just doing my best to catch up on what I have missed. I'm confident my hard work will pay off."

The 23-year-old has scored two goals in 15 appearances for United.