Fergie to ring the changes

Despite the enormity of their meeting with David Moyes' side, the Red Devils will be virtually unrecognisable from the team that started in Portugal as Wayne Rooney, Cristiano Ronaldo, Ryan Giggs and Michael Carrick are all expected to stand down - with Edwin van der Sar and Dimitar Berbatov possibly joining them.

"When I pick my team, no matter what it is there will be critics voicing a concern about me not playing my strongest team," said the United chief. "Not everyone agrees with changes. There are some supporters who want me to play my best team every game. That is impossible. If you look at Wednesday's game you are off your head to think I could play the same team again."

The sheer energy expended in United reaching the last four of Europe's number one club competition for the third season in a row means the men asked to do the bulk of the running will not be asked to put their bodies on the line again.

It means Rooney is set to miss out on an emotional last four meeting with his former club, with Ronaldo due to sit the game out as well having toiled on his own up front for the last half hour.

"I am in a difficult position because we have got so many hard games coming up," reflected Ferguson. "Somewhere along the line I have to make changes.

"The speed of the game has changed.

"Look at how fast the Premier Division is. The intensity of the matches is the reason English teams have a head start in Europe."

Yet Ferguson also denies he is devaluing the FA Cup. Replacements such as Park Ji-sung, Darren Fletcher and Carlos Tevez are all senior internationals who have been integral figures in United's pursuit of an unprecedented quintuple this term.

"Hand on heart, the FA Cup is important," he said. "We don't want to have a defeat at this time of year. No matter what the defeat is, we have to answer for that."