Sir Alex Ferguson has said he does not believe anybody will beat Wayne Rooney's Manchester United goal scoring record.
Rooney, 31, superbly notched his 250th goal for the club on Saturday, bending home a free-kick to secure a last-gasp 1-1 draw at Stoke and move clear of Sir Bobby Charlton's landmark.
The World Cup winner called Rooney a "true great" after he broke a record that has stood since 1973.
The forward, who has been at Old Trafford since 2004, is in a period of transition and speculation about his future -- but Ferguson believes his record could well stand the test of time.
"When Wayne Rooney joined the club I could never imagine anybody could beat Sir Bobby's record," Ferguson told MUTV.
"So 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.
"I don't think anyone can [overtake Rooney]. 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 but we were very lucky if you look at my time, even in Sir Matt Busby's time, we had players who stayed for more than 10 years.
"Many, many players did that. But in the modern day, you see it happening less and less that players stay for that length of time.
"For instance, Jose [Mourinho] mentioned young Marcus Rashford and he's got to score more than 20 goals a season for the next 10 years or so [to beat Rooney's record] and that is difficult in itself."
Ferguson made Rooney the most expensive teenager of all time when signing him from Everton for around £30 million -- a deal that now looks like a snip.
"The only way you can assess value is the length of time he has been at the club," the former United boss said.
"I was very lucky in my time to have Roy Keane for 11 years, Steve Bruce for a long period, Peter Schmeichel for years, Dennis Irwin.
"The young ones that came through like Ryan [Giggs], Paul [Scholes] and Gary [Neville] lasted more than 10 years. The only way you can really judge value is the length of time you've got with them.
"So the only way you can judge is that and, with the case of Wayne, what we felt at the time that he was 18 years of age, he had huge potential. The value was there, no question."