Gary Neville is David Beckham's best mate, he knows the score. The pair have seen most things in football together, from Manchester United's youth team to 1999's Treble to their present status as automatic England selections, but when Neville broke the same obscure bone in his foot as Beckham in the very next Champions League fixture at Old Trafford, he would not have been expecting the nation to go into mourning all over again.

Nor did it. Full-backs very rarely earn the affectionate nickname Goldenballs, make it into the title of hit movies or have the Prime Minister fretting about whether they will recover in time for the World Cup. Beckham is unique, which is not something the down-to-earth Neville has ever had a problem in accepting, but it does not follow that this latest blow to England's hopes can be shrugged off simply because Sven-Göran Eriksson has several more right-backs to choose from.

True, it is easier to think of names to fill the vacancy than was the case with Beckham, but that is not quite the same thing. Eriksson will be hugely disappointed if his most experienced outfield player is unavailable for, with over a half century of caps dating back to Euro 96, that is what Neville is. Of the present regulars, only David Seaman predates Neville in the England team. Gareth Southgate and Teddy Sheringham were there before him, but have not been regulars since and do not have quite as many caps. Other players nearing the 50 mark, such as Sol Campbell and Beckham himself, arrived only after Glenn Hoddle succeeded Terry Venables. Neville was also in the frame for the England captaincy before Eriksson awarded it to Owen.

So, like Manchester United, England have been particularly unlucky to lose their two most dependable players to an injury that no one had ever heard of until three weeks ago. Beckham is given a good chance of being fit in time for the World Cup, Neville is unlikely to go, given that at best he can hope only to return after the group stage. The worst aspect from both club and country point of view is that the most solid area of the team, the right-flank combination, which until this month has never given Eriksson or Ferguson a moment's worry, has been disrupted for the foreseeable future.

Of course England could just call up Jamie Carragher or Wes Brown to play right-back and not lose too much defen sive cohesion, but Neville offers much more than those two when getting forward. Phil Neville and Danny Mills are more adventurous full-backs but less tidy when defending, and neither shares Gary Neville's admirably unflappable temperament. Both would be likely to collect yellow cards in a World Cup tournament. Owen Hargreaves may be the best bet, perhaps the most exciting choice, but he would need the one thing he has not got - time - to replicate the elder Neville's instinctive understanding with Beckham.

Neville's overlaps often give Beckham the option of either using him or cutting inside. If he releases the ball he can be confident of a cross struck almost as crisply as one of his own, if he carries it infield he knows Neville will drop back to cover the unoccupied wing. This is hardly rocket science, but it is surprising how many United chances have their origins in simple interplay between the two right-wing men. In defensive situations, Neville can be equally sure that Beckham will chase all the way back with his opposing winger to ensure he never has to deal with two men on his own.

There was a telling moment in the first half against Bayer Leverkusen on Wednesday when the German side easily reached the goalline down the left wing by passing around Neville, who looked up despairingly to find stand-in winger Juan Veron observing the proceedings from a static position just inside the halfway line like a latter-day Stanley Matthews. The simple chemistry between Neville and Beckham should not be underestimated, and neither should their closeness off the pitch. Beckham, a young captain of a young side, will miss his closest ally if Neville has to spend the summer at home.

Before the World Cup, however, United have one or two small Champions League fixtures to fulfil. Everyone knows they have a squad large enough and talented enough to cope with injuries on the way, but there is a limit to the number of senior players even Manchester United can afford to lose and still entertain the notion of winning the European Cup. What was evident on Wednesday was that Leverkusen were pumped up for a semi-final, right on top of their form, whereas too many of United's most famous individuals were not. Ruud van Nistelrooy played as if the Footballer of the Year award had sucked all the talent out of him. Too often his first touch was ordinary, and he missed a couple of sharp chances he might normally have bagged. Ryan Giggs could not find the touch and subtlety he demonstrated against Chelsea last weekend, while Veron, not helped by being asked to play on the right, was far from the towering influence he ought to have been in the absence of Beckham and Keane.

The Irish captain will be back for the second leg, and Ferguson has already evoked the memory of his heroics in a similar situation in Turin in 1999, but Keane can hardly be expected to beat Leverkusen on his own. United will need heroics from the support staff as well, which is precisely why they can ill afford to lose players of Neville's calibre. 'We think Gary actually picked up the injury in the Chelsea game,' Ferguson explained. 'It's something we could have done without, but I don't think it's anything to lose sleep over for Tuesday's game. Denis Irwin can slot in there and he's got bags of experience. Laurent Blanc is likely to be fully fit again, so I'm looking at him and Wes Brown for central defence. We can patch ourselves up for the semi-final, and defence is not the area where the game will be decided. The key issue in Leverkusen will be midfield.'

Ferguson has formed that opinion not because of the excellence of Michael Ballack, Carsten Ramelow and Bernd Schneider last Wednesday but because two essential components of his own midfield are recovering from injury. He does not think he is taking too much of a risk in bringing Keane back so quickly after a hamstring tear - 'Roy has been training like a beast all week' - but the full Captain Fantastic performance might be a lot to ask of a player who has been sidelined for three weeks. Veron, who has tended not to shine when asked to play alongside Keane in any case, is also struggling with an Achilles injury, which he may end up taking to the World Cup.

'There's no time now to treat it before the end of our season, but I imagine he'll be well looked after by Argentina in the couple of weeks before the World Cup starts,' Ferguson said. 'I'm sure he'll be ready for the World Cup, but our immediate problem is to have him ready for Tuesday. He tired noticeably in the second half against Leverkusen, so we are going to train him really hard over the weekend to make sure he is strong enough for a full game.'

Ferguson thought Paul Scholes and Nicky Butt were United's two best players in the first leg, although Ole Gunnar Solskjaer, also operating in midfield, did not do too much wrong. The task now is to decide which player will support Van Nistelrooy in attack, and select a midfield capable of taking on the energetic and inventive Germans. If Leverkusen were not standing between United and their last hope of silverware this season, Ferguson would probably admit to a sneaking admiration for their style. Like his own side, they find it hard to suppress attacking instincts. 'They started off patiently against us, but when they went a goal down they reverted to their natural game and looked more comfortable than we did,' he said. 'I don't know why, but we were nervous. I think the second leg might be similar, but we won't be nervous and I'm sure we'll play better. They have an advantage, but it will only come into effect if the game is a draw. I think there will be more goals, though maybe not as many as people think. It's still an open contest.'

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