Rafael Nadal's surprise semi-final exit from last week's Thailand Open is further indication that the Spaniard intends to take notice of the warning signals he receives from his creaking body. Nadal, still only 24 and presumably with more productive years ahead of him, is firmly re-established as world No 1. Fitness permitting, it appears he is on course to outstrip Roger Federer as the greatest player in the history of the sport.
Such a suggestion would have been considered outrageous at the start of this year when Federer extended his record haul of grand slam titles to 16 by overcoming Andy Murray in the final of the Australian Open. Since then, however, the season has been Nadal's to the extent where a clean sweep of slams looks inevitable when he returns to Melbourne in January as holder of the French Open, Wimbledon and US Open titles.
To stay on course for a 10th major title and keep Federer's record as a realistic target, Nadal knows he can ill afford to spend as much time off court as he did last year. That means he has to be selective when it comes to giving it his best shot and equally astute in deciding when to drop down a gear. It is no coincidence that his six titles this year have come in the main events - three Masters Series triumphs preceding his three slams - and it would be no great surprise if his seventh came in next week's Shanghai Masters, rather than in Tokyo at the weekend when he is scheduled to meet Andy Roddick in the final.
There is a fine balance between easing off the gas and allowing a supposedly inferior opponent the chance of a victory and committing the cardinal sin of losing deliberately. Nadal and Federer have become adept at satisfying the requirements of supporters and sponsors on their world travels before departing a round or two earlier than expected from the less important tournaments in order to be in prime shape for the ones that really matter.
So, expect Nadal to give his dodgy knees a relatively easy time in Tokyo before going full out in Shanghai and the concluding Masters Series event in Paris next month which precedes the ATP Tour finals in London - an appealing seasonal finale for the Spaniard in view of his country's failure to reach a third successive Davis Cup final.
