Ryan Giggs turned in a scintillating performance as Manchester United eased into the FA Cup quarter-finals with a 4-1 victory over Derby at Pride Park.

Giggs did not get his name on the scoresheet as Nani, Darron Gibson, Cristiano Ronaldo and Danny Welbeck took the honours.

But he was at the centre of all the good work United produced on an eventful afternoon which leaves him just three wins away from becoming the first player since the 19th century to collect five winners' medals in this most historic of competitions.

Six weeks ago, United came to the same ground and were humbled as Derby basked in the glory of Nigel Clough's appointment.

The Red Devils reversed that result to book a Carling Cup final place, since when they have enhanced an unlikely quintuple bid by taking a stranglehold in the Barclays Premier League title race.

Keen to ensure there was no repeat east midlands horror show, Ferguson sent his team - showing seven changes from the one that defeated West Ham last weekend - out with a sense of determination.

Stephen Bywater was twice called upon to keep the visitors out, first denying Nani with a low save, then pulling off an amazing reaction effort to repel Park Ji-Sung.

But it was already pretty obvious Derby needed an unexpected turn of events to emerge victorious and once referee Alan Wiley had rejected Rob Hulse's claims for a penalty when he went down under Rio Ferdinand's challenge, it was always unlikely to come.

Nani seems to have lost his way a little in his second season at Old Trafford, yet he remains capable of those moments of genius for which compatriot Ronaldo is so famed.

And, when he collected Ryan Giggs' square pass and raced across the penalty area, the fierce 20-yard shot that followed was nothing out of character as it left Bywater with no chance.

One Kris Commons free-kick that tested Ben Foster was about all Derby could manage in response before a bizarre period followed in which United were denied a goal that should have been allowed, and given one that should have been ruled out.

Ronaldo's celebrations were cut short by a very late flag after he raced clear and slotted the ball past Bywater. The officials needed to confer before acknowledging Giggs had flicked Ben Foster's long throw through to the Portuguese superstar.

Ferguson was not happy, making his feelings known to fourth official Rob Styles in no uncertain manner.

United's grumbles did not last too long, although how Rafael was not ruled to be offside as he ran straight in front of Bywater as Gibson volleyed in was a mystery.

Any lingering doubt over who would be in the last eight was removed within three minutes of the restart.

Giggs was again the provider, this time in routine fashion with a near-post corner which Ronaldo powered home, his elaborate celebration suggesting his 15th goal of the campaign should have come earlier.

To all intents and purposes, it was game over, even if Miles Addison guided home a header to pull one back for Derby almost immediately.

Ronaldo spurned a couple of chances to add to his tally, with Darren Fletcher failing to profit from a rebound.

Enthusiastically Derby pressed forward in reply, Gary Teale bringing an excellent save out of Foster, handed a rare start ahead of Edwin van der Sar.

But United were too good, with Giggs in particular truly majestic.

At 35, with a barrow-load of trophies already, it could be argued the former Wales skipper is playing more consistently well than at any stage of his career.

It still rankles with Ferguson that in the 1999 treble-winning season, Giggs, along with the remainder of United's squad, was overlooked for all the major individual prizes in favour of David Ginola.

He further enhanced his credentials for this season's player prizes by playing a role in Danny Welbeck's late effort.

Teams

Derby Bywater, Connolly, Addison, Albrechtsen, Stewart,Barazite (Sterjovski 63), Green, Savage (Pearson 82), Teale,Commons, Hulse (Porter 68).

Subs Not Used: Carroll, Nyatanga, Davies, Todd.

Booked: Connolly.

Goals: Addison 56.

Man Utd Foster, Rafael Da Silva, Ferdinand, Evans,Evra (O'Shea 55), Park (Welbeck 55), Fletcher, Gibson, Nani,Giggs, Ronaldo (Possebon 72).

Subs Not Used: Kuszczak, Vidic, Scholes, Tevez.

Goals: Nani 29, Gibson 44, Ronaldo 48, Welbeck 81.

Att: 32,103

Ref: Alan Wiley (Staffordshire).