The Scottish manager admitted that, when Rooney joined the Red Devils, he never expected him to become the team's all-time top scorer.

Beating Wayne Rooney's goal scoring record for Manchester United might be too hard to surpass, and one of his former coaches believes it could end up lasting forever.

Speaking in an interview with MUTV, the legendary manager opened up about his feelings after Rooney's record-breaking goal, and even stated that the milestone could be everlasting.

"Well, it lasted for 44 years, I think, and when Wayne Rooney joined the club I could never imagine anybody could beat Sir Bobby's record. His achievement is outstanding, it's amazing. He's 200-odd games short of Bobby's playing record and that makes it even more amazing,"Ferguson stated.

The former Man Utd boss explained why he believes that Rooney's record could taken even longer to be surpassed.

"I don't think (anyone can overtake Wayne). I couldn't say never - never say never - but if you look at modern-day football, Manchester United are one of the few clubs who can keep players for over 10 years. It is more difficult than ever," Sir Alex added.