Sir Alex Ferguson has given his backing to Manchester United's doctors after Owen Hargreaves hit out at the treatment he received during four injury-plagued seasons at Old Trafford.

Hargreaves was released by United at the end of last season and joined Manchester City over the summer after proving his fitness, making a goalscoring debut for Roberto Mancini's side in midweek.

He endured a torrid time with knee problems during his stint with United and claimed on Friday morning that he felt like a 'guinea pig' while having treatment with the Red Devils.

United will release an official response later on Friday but Ferguson insisted in his pre-match press conference for Saturday's clash with Stoke that he had complete faith in his medical staff.

"We've been trying to analyse all the stuff he said and we're going to give a club statement this afternoon to address that," Ferguson said on Sky Sports News.

Fantastic

"But as far as I'm concerned my medical staff are one of the main reasons Manchester United have been so successful over the last few years, there's no doubt about that.

"I have got a fantastic medical staff, great sports science.

"Do you think we would be successful if they were not 100 per cent brilliant?

"Our doctor and his five physios are fantastic - that is my opinion and that is more important than what anyone else has to say about it."

Hargreaves suffered from persistent tendinitis while at United, resulting in the player undergoing double knee surgery during the 2008-09 season.

Following the operations, Hargreaves played just six minutes of first-team football as he battled to regain fitness prior to being let go.