The Davis Cup final comes down to today's singles and may change the life of a teenage prodigy for ever.

There are those who mature patiently into greatness, others who demand it before their time is really due. Should Rafael Nadal be the man who wins Spain the Davis Cup for only the second time today, he will be afforded reverence rarely attributed to an 18-year-old. But he will watch compatriot Carlos Moya�s opening rubber against American Andy Roddick with mixed emotions. If Moya wins, Nadal�s encounter with Mardy Fish is meaningless.

Victory for Roddick will offer the teenager the chance to become a Spanish hero. Precocious, seemingly unfazed by a nation�s expectancy and possessing both talent and sheer brute force, Nadal is unquestionably a grand slam champion of the future. Whether he also ascends to the position of World No 1 will depend on how long Roger Federer maintains his dominance, but it is easy to draw comparison between this startlingly gifted Majorcan and a young Boris Becker.

Watch Nadal clumsily try to explain his victories and he appears every bit the immature youth. He pulls funny faces, shrugs his shoulders, doesn�t even attempt English and struggles for the right words in his native tongue. Yet watch him on a tennis court and he is transformed into a ruthless matador, drawing his opponents in and going for the kill. His sprightliness on court can only currently be matched by Lleyton Hewitt, but the Spaniard possesses so much more power.

Roddick has won all three of his previous meetings with Moya. Admittedly, none have been played in front of a crowd of 27,000 partisan Spaniards. But if Nadal is asked the ultimate question, his teammate believes he will be able to provide the right answer.

�There is nothing that Rafa cannot achieve, he is such a terrific talent,� enthused Moya, who, like the youngster, shattered the belief that the only thing to come out of the Balearic island of Majorca is toy donkeys and short-lived holiday romances. �I first saw him as a 12-year-old and was immediately impressed by his potential. He does not worry about reputations, he is not troubled by any situation, from that first day I sensed he wanted to take on and beat opponents far older and experienced than himself.�

Just a few weeks ago it seemed that Nadal would play only the role of a doubles player in this final, but the catastrophic plummet of Juan Carlos Ferrero�s self-belief prompted the triumvirate of Spanish captains to thrust the youngster into a singles role. Ferrero was left dismayed, Nadal, calmly aware of his responsibilities and the measure of his victory over Roddick, makes the possibilities of today mouth-watering. Earlier this year he became one of the few players to overcome Federer at a time when the Swiss was beginning to stir minds into thinking he was quite possibly the greatest of all time.

Sadly, Nadal�s progress was then halted by a serious ankle injury that kept him out for three months, but he has used the Davis Cup as a platform to enhance his name and the win against Roddick was the sort of thing to stir more than just the imagination.

That the final is still alive is down to a not entirely unexpected victory in yesterday�s doubles match by American twins Bob and Mike Bryan, who overcame the stand-in Spanish pair of Ferrero and Tommy Robredo 6-0 6-3 6-2.

The Bryans, currently ranked as the second best doubles team in the world and undoubtedly the most symmetrical, with left- handed Bob and right-handed Mike, maintained their unbeaten Davis Cup record.

Baseliners do not competitive doubles players make and approaching the net is traditionally as alien to natives of this country as eating their evening meal as early as 6pm. Admittedly, there were hopes of doing a little better than in last year�s final, when the collaboration of Alex Corretja and Feliciano Lopez managed to win seven games against the Australians on the inhospitably-laid grass of Melbourne.

But the Bryans are a partnership that not only has the benefit of brotherly telepathy but a coded signalling system with their fingers akin to that used by baseball players.

If the Americans do recover from the 2-0 opening day deficit to win the competition, so becoming the first final contestants in 65 years to accomplish such a feat, there will certainly be reason for another Spanish inquisition. �We are still leading 2-1, we are extremely motivated as we are going to win,� insisted Jordi Arrese, designated front man and spokesman of the nation�s unusual three-man captaincy committee that prefer to be known as G3. �All our choices for the final day are completely open. Rafael is rested. Carlos Moya is motivated and ready to go.�

Patrick McEnroe, the US captain, remains bullish. �We know what we are up against but by no means do we think we are out of it,� he said. �We are the underdogs but we have been that from the moment we landed here more than a week ago. You have to expect that the crowd is going to be really loud and clap after our guys miss a serve. But we will keep our heads down and go about our business like Bob and Mike did. Winning this thing is still not out of our reach.�

Such a prospect is unlikely and the wisdom of McEnroe�s selection of Fish is likely to be debated for many months.