Just hours after Real Madrid president Ramon Calderon claimed the deal hinged on the London club's willingness to do business, Robben was left at home by the Blues as Frank Lampard's leveller enabled Chelsea to keep their unbeaten pre-season record intact.

The Barclays Premier League club, winners of the FA and Carling Cups last season, have shrugged off all previous attempts by Madrid to land the Holland international.

Now any proposed deal could be scuppered by the fitness of the 23-year-old winger.

Chelsea assistant boss Steve Clarke confirmed: "He's got a small problem with his knee. He stayed behind for treatment. It's not major - we've decided to rest him for a week to 10 days, and he'll be fine after that. He's still a Chelsea player."

Madrid have been closely linked with Robben throughout the summer but have failed to persuade Chelsea to part with the player - even after the Londoners added Lyon winger Florent Malouda to their squad.

Madrid now want to strengthen their own squad still further and have again identified Robben as their key acquisition.

Chelsea's billionaire owner Roman Abramovich recently insisted Robben would not be sold at any price, but negotiations over a new long-term deal with the player appear to have broken down.

The 23-year-old was in the process of negotiating a new four-year contract at Stamford Bridge, but there are increasingly ominous signs that it is now only a matter of time before Madrid finally get their man.

Calderon said: "We are advancing in the negotiations. Those responsible are doing it very well, and I hope that it comes to fruition. But until the agreement is closed, we cannot say anything.

"It has to be the selling club who first decides - and once that has happened, I don't suppose there will be any problems resolving the player's contract."

Chelsea coach Jose Mourinho wants Robben to stay and sign a new deal. But the Dutchman, whose personal affairs are conducted by his father Hans, will move on if the Blues decide it would be better to cut their losses.

Robben has two years remaining on his current deal with Chelsea, but their reluctance to increase his wages on a par with the likes of other stars at Stamford Bridge has frustrated him.

Chelsea remained unbeaten following their successful American tour, thanks to a late equaliser against Feyenoord and a penalty save from substitute goalkeeper Carlo Cudicini.

The Dutch side took the lead just before half-time with a header from defender Kevin Hofland - and after Lampard's leveller, Cudicini capped a fine second-half performance with a penalty save from Roy Makaay.

Clarke added: "Carlo made a couple of good saves. I think that was a bit of justice. It's always good when your goalkeepers are showing good form at this stage of the season."

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