Manchester United hero Denis Irwin rates Owen Hargreaves as Sir Alex Ferguson's most important signing this summer.

"Hargreaves really adds something to the squad because I don't think we've got a player like him in the current side," Irwin told MUTV. "He had a fantastic World Cup last summer and I just feel that he is going to be our biggest summer signing."

The signing of Hargreaves ended a year-long chase to bring the 26-year-old England international to Old Trafford. Irwin firmly believes it will be well worth the wait, adding that Bayern Munich's reluctance to sell is a very good sign.

"He's got experience having played for Bayern Munich for seven years," he said. "And their determination to keep him just shows how valuable he was and how highly they regarded him. I think he's going to be a really good signing for us."