The Red Devils are 12 points clear as they pursue another Premier League title and their campaigns to win the FA Cup and Champions League are still going strong.
Sir Alex told reporters of the strength he feels that his side possess, which he hopes can help their chances of recreating the 1999 successes.
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"I think it's nice to look back at these things and how it was done in that particular time with the squad of players I had, which is not nearly as strong as the one I have now.
"It's not just the four strikers I could change, you could change the entire team now. There were good internationals who weren't even involved on Wednesday [against Real Madrid].
"It will be a different team when Madrid come here. One, two or three who didn't play on Wednesday could play in the second leg. I've got all these international players, so why shouldn't I trust them?
"The way I'm looking at it is to pick a team to win the next match and it will be a different team against Reading and again against QPR, Norwich City and then Madrid."
Manchester United face Reading in the fifth round of the FA Cup on Monday, when a victory would bolster their chances of winning a trophy which has been absent from the Old Trafford cabinet for almost 10 years, their last triumph coming over Millwall in 2004.