Vidic is in the middle of a rehab programme after suffering a season-ending knee injury last December, while Van der Sar retired after United clinched the Barclays Premier League crown last May.

'They've been playing without me all season and Nemanja got injured quite early on, so they will be okay,' Van der Sar said from London. 'Along the way the younger players have stepped up their performances, while the return of Paul Scholes was one of the turning points.'

On the face of it, Manchester United's defence has again been stingy this season - conceding just 32 goals in 35 matches, which is the second best in the league behind their local rivals. But, by their incredibly high standards, their level has actually slipped at home. They've let in 19 goals in 18 matches, compared to just 12 during the entire 2010-11 campaign.

Rio Ferdinand and Johnny Evans have deservedly won praise for their partnership, especially on the road, where United have conceded just three goals in their last five matches.

But they've had lapses at Old Trafford, including last weekend's shock 4-4 draw that saw Everton score twice in the last seven minutes.

Despite his brilliant shot stopping, David de Gea has had enough shaky moments to give Red Devils' fans jitters ahead of Monday's crunch match. The Spaniard's slight physical frame means he's been overpowered from set pieces as big defenders throw their bodies forward.

He certainly hasn't been able to command his box in the same way Dutchman Van der Sar and Denmark's Peter Schmeichel did for a combined 14 seasons for the Red Devils.

Even so, Van Der Sar is confident De Gea will handle the occasion, despite conceding six goals in the last league meeting between the sides in October. He said the youngster was used to derby games, having played for Atletico Madrid against Real Madrid in La Liga.

'United went from a 40-year-old to a 21-year-old so I think it's only normal De Gea made a couple of wrong judgments and had some adjustments to make because it's a different, more physical league with more corners,' Van der Sar said.

'But his performances over the past two to three months helped United close the gap on City and then open up a gap themselves. I'm not worried about him.

'He just has to get his head down and focus on all the things he's done over the past couple of months.'

Van der Sar also had high praise for City's Joe Hart, who has played in all 35 of City's league games this season and kept 15 clean sheets, having won the Barclays Golden Glove in 2010-11. He's been such a constant in the line-up that it's difficult for many casual fans to name the Sky Blues' reserve custodians.

Turning 25 last week, Hart will be England's first choice at Euro 2012 in June. After the 2010 World Cup where he was an unused reserve, Hart had just three international caps - he now has 17 and is even being touted as a future captain.

'I saw him coming up during my time at United and I was very impressed,' Van der Sar said. 'I know he's not really a local boy, but he did come through the youth set-up. He seems to have grown bigger and got stronger.

'De Gea hasn't filled out yet and I know they're working towards beefing him up through weight training. I'm sure that [United goalkeeping coach] Eric Steele has shown him videos so he can learn from situations that have happened before.'

In the Netherlands, Monday is a public holiday - Queen's Day - and Van der Sar will watch the game with friends at his home, 30 minutes outside of Amsterdam.

He's hoping the derby won't be decided by a goalkeeping error, especially by his successor.

'In terms of his footwork, ball skills and distribution to the midfield and the forwards, De Gea looks similar to how I played,' he said.

'So let's hope we see a good game with no mistakes and maybe a goal from United in the last minute to dash the hopes of City. I'm predicting a nice little 1-1 draw.'

It could turn out to be a tale of two goalkeepers.

Whoever holds his nerve better under the floodlights will almost certainly be celebrating Premier League success just 13 days later.