When the 6ft 6ins Juan Martin Del Potro raised his arms into the New York sky last September after conquering a resurgent Roger Federer in the final of the US Open, the young Argentine looked the man most likely to usurp the Swiss at the top of the world rankings. Now a distraught Del Potro faces the worrying prospect of falling headlong down the tennis ladder after going into an enforced exile while he gives a wrist injury every opportunity to right itself. There is no time limit on when he will be back.
Del Potro, a formidable figure for a man who still only 21, sustained the painful blow while building up for the Australian Open in January and has not been seen in competitive action since losing in the fourth round of the Melbourne grand slam to Marin Cilic. Hindsight is a wonderful thing but surely he will today be regretting his decision to delay surgery until this week as he fought to overcome the problem.
The joint could have been well on the way to healing by now if he had addressed the issue immediately and a second grand slam title in Paris next month - he lost a marathon five-set semi-final to Federer, the eventual champion, last year - would have been a distinct possibility. Andy Murray, one of Del Potro's biggest rivals during the advance of tennis's younger brigade, did just that after being struck down by excruciating pain when leading Filippo Volandri, his Italian opponent, 5-1 in the Masters Series event in Hamburg three years ago this month.
Although it brought the despair of missing the French Open and Wimbledon to a British player who was emerging as a future grand slam champion, it meant Murray could return inside three months to rebuild a career which has since prospered with the appearance in a two grand slam finals to go with his 14 professional titles. It is to be hoped for the good of the men's game that Del Potro eventually returns as fit and as strong as Murray did. Tennis badly needs new rivalries to match the one which Rafael Nadal had with Federer before the Spaniard was cut down in his prime by injuries to both knees. Nadal's unfortunate decline - thankfully the former world No 1 is back to something like the imperious form that made him the King of Clay and also brought glorious triumphs at Wimbledon and in Australia - was attributed mainly to the wear and tear of riding continuously on tennis's global bandwagon.
One of the most impressive physical specimens in the game when he emerged as a marauding teenager, Nadal has more recently been as outspoken as any in a campaign to lessen the demands made on the world's leading players. Federer, who has been blessed with a relatively uninterrupted career, has been a powerful ally in this and the Swiss has begun to deal with the issues himself by making unpopular but astute decisions to reduce his schedule.
Dubai, Federer's second home and a happy hunting ground over the years, was the latest tournament to suffer from his steadfast refusal to take any chances with his health. The world No 1 disappointed fans in the Emirates by making a late withdrawal from this year's big event at the Aviation Club due to a lung infection. Federer could not be criticised for his caution after being struck down by glandular fever in the early part of 2008 - an illness which saw him outshone by Nadal for the ensuing 12 months - before normal service was resumed in the middle of last year.
Before winning an elusive first title at Roland Garros in the middle of the last campaign and following it with a record-breaking 16th grand slam success at Wimbledon, Federer was being written off by many pundits. Carefully looking after his valuable limbs has enabled Federer to carry on enjoying the fruits of his labour in rising to No 1 status, unlike Nadal and in recent times Australia's Lleyton Hewitt and Russia's Marat Safin, both of whom failed to capitalise on their brief periods at the top of the rankings due to lingering fitness problems.
Del Potro, who on Monday slipped from fourth to fifth in the ATP rankings following his failure to appear in last week's Rome Masters, undoubtedly possesses the armoury to follow them into that exclusive club of top-ranked players. Whenever the man from Tandil finally resumes his challenge for that privileged honour, he is likely to have to pass more than the four men who are currently in front of him.
That task will become even more daunting if he does not defend the bucketful of points he won during the autumn hard court season in North America when he supplemented his Flushing Meadows highlight with a win in Washington and a runners-up spot to Murray in Montreal. @Email:firstname.lastname@example.org