Manchester United boss Sir Alex Ferguson admits their penalty blunders are becoming an issue.

In their FA Cup win over West Ham United, Wayne Rooney's failed effort from the spot at Old Trafford, blazed high over the bar in the 79th minute, leaves United with a record of four penalties scored and five missed for the season so far.

Asked about that after the game, Ferguson told MUTV: "I don't think it is just one of those things.

"I think we have to improve at that.

"If you get a penalty kick, really... there has been talk about (the good penalty record of) Rickie Lambert at Southampton. That is what taking penalty kicks is about.

"There have been several great examples over the years - (former Southampton midfielder) Matthew Le Tissier scoring 47 out of 48.

"A penalty kick is your opportunity to take advantage of a foul or a handball or whatever and score a goal."