Tomorrow, 24 hours after United have tackled Chelsea in the Barclays Premier League, is the 20th anniversary of Giggs' debut, as a raw 17-year-old against Everton.

During the intervening two decades, the Welshman has served just one master.

And although Giggs is convinced Ferguson could remain in his job for a further "four or five" years, when the Old Trafford hierarchy eventually meet to appoint a successor, the test will be stiff indeed.

"It is a massive challenge," said Giggs.

"We are talking about the most successful manager ever.

"He is constantly evolving, trying to get the age of the team right, so that will help the next manager.

"Also, you normally take over when a team is struggling but hopefully this team will be in good shape.

"It's not impossible but it is going to be tough."

Not that Giggs will be thinking too much about Ferguson's future, or his own for that matter, when he stands by to make his 863rd appearance, and a record-equalling 606th in the league, against Chelsea tonight.

As is always the case, Giggs accepts the accolades with good grace, then quickly dismisses them as something to look back on when his playing days are over.

For now it is the small matter of Chelsea and another step towards a 19th title, of which he will have played a part in 12.

"There is never a time when you can rest on your laurels," he said.

"When you've beaten a record there's always some game you've got to concentrate on. You don't really have time to think too much about what you've done and they don't come any bigger than Chelsea away."

United have not won at Stamford Bridge since 2002 but they will be bolstered in their attempt to end that record by Wayne Rooney, who did not get charged by the Football Association for his clash with James McCarthy at Wigan on Saturday.

World governing body FIFA remain implacably opposed to the use of video technology and frown severely on matches being re-refereed, no matter how obvious the mistake.

Consequently, once the FA had contacted referee Mark Clattenburg to establish the free-kick he awarded was for a clash he felt Rooney instigated, there was little option other than to declare the case closed.

It was a situation United quickly became aware of, with Clattenburg's bosses insisting their man was right.

"Mark took the correct course of action with this incident," said Professional Game Match Officials general manager Mike Riley.

"In this incident Mark caught sight of two players coming together and he awarded a free-kick because he believed one player had impeded the other.

"We should be clear that Mark did nothing wrong in officiating this incident as he acted on what he saw on the pitch."