With another meeting against Real Madrid looming next Tuesday, Ferguson knows he must get his team selection right at Old Trafford if United are to stand any chance of progressing to the quarter-finals.
That is bound to mean disappointment for some, as it did in the Bernabeu a fortnight ago.
On that occasion, skipper Nemanja Vidic headed a list of high-profile omissions, with neither Ashley Young nor Nani included either.
After watching Real hammer Barcelona in the Nou Camp last night in the first of back-to-back `El Clasicos' prior to Jose Mourinho's men heading to Manchester, Ferguson knows how important it is that he makes the correct calls.
Yet, even for those who miss out, the United boss can point to a very real example to prove it does not necessarily mean they can never have an impact with the Red Devils.
"In 1999 I left Paul Scholes out of the quarter-final against Inter Milan yet he was the one who scored the goal that got us through," Ferguson told MUTV.
"I left him out of the semi-final because I couldn't risk him and Roy Keane together as they were both on yellow cards. He accepted it graciously, came on, got booked and missed the final anyway.
"What did he do? He didn't let it affect him. He went on to become one of the greatest players this club has ever had.
"The players sense it could be a big year for them.
"But at this club, in this situation, anything can happen on the run-in. Players can all of a sudden find themselves playing in a final or an important league game because that is the kind of squad I have."
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