were hailed as English football's modern invincibles after crushing Derby County 4-1 at Pride Park to cruise into the last eight of the FA Cup.
Even without some of their biggest names Sir Alex Ferguson's Barclays Premier League champions blew away Nigel Clough's team with goals from squad men Nani, Darron Gibson and Danny Welbeck as well as Cristiano Ronaldo.
United visit Swansea or Fulham
in the quarter-final after last night's draw kept them and other Cup favourites Arsenal
apart. Everton had earlier beaten Aston Villa
After United's win, Derby boss Clough was asked if Ferguson's side could win an unprecedented five trophies this season and said: 'It's possible. If anybody can, they can. We've played them three times in cup competitions this season and that was the best performance they've put on against us. If they had played Arsenal, Chelsea or Liverpool today, then they could have put four past them as well.'
One moment of controversy briefly threatened an entertaining game as photographs appeared to show United winger Ronaldo spitting in the direction of Derby midfielder Robbie Savage.
But Savage later denied there had been a problem and said: 'Nothing went on. It didn't happen.'
'Nothing happened': Savage (right) and Ronaldo clash
Derby may have taken some encouragement from United's teamsheet with WayneRooney, Dimitar Berbatov, Paul Scholes, Nemanja Vidic and Carlos Tevez not starting.Ferguson's team also did not include a recognised centre forward.
But Ronaldo and Ryan Giggs ran the game for United as the visitors illustrated their remarkable strength in depth.
Clough added: 'It is impossible to prepare against them as you can watch them six times and they will play a different team every time. How do you prepare to play Ryan Giggs? He can play anywhere. It's incredible.'
The master: Sir Alex Ferguson has already won one pot this season - how many more will he get his hands on?
United may have Rooney back for the Premier League visit of Fulham on Wednesday, when victory would take them five points clear, and they also have key games against Blackburn at the weekend and at Inter Milan in the Champions League last 16 a week tomorrow.
Ferguson, who has already won the Club World Cup and has led United to the Carling Cup final, said: 'We're one step from the FA Cup semi-final and hopefully we can maintain the levels we've shown in recent weeks.
United already have one trophy in the bag this season after victory in December's World Club Cup
'The squad have been getting us through these difficult games. We made changes today with Wednesday's game in mind.'
Everton's win over Villa gave boss David Moyes a home quarter-final againstMiddlesbrough
or West Ham
The Hammers are awaiting the results of a scan today on England forward CarltonCole's damaged ankle. He faces a fortnight out.
PICTURE SPECIAL: Savage and Ronaldo spat ruins Derby day
Derby 1 Manchester United 4: All the action as it happened
Derby 1 Manchester United 4: Flipping awesome Red Devils ease into the last eight
FA Cup quarter final draw: Big three separated as Manchester United, Chelsea and Arsenal await replay fate
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