Cycling: Invincible Lance prepares for his perfect finale

On Saturday, for the first time since the Tour de France began 102 years ago, its star rider will roll down the starting ramp of the opening time- trial with a unique new objec-tive: in the words of Lance Armstrong, "to retire on top of my game".

The 33-year-old American has already achieved the near-unthinkable: last year he notched up a record-breaking sixth Tour win. Not only that, in the 2004 edition he clinched four mountain stages out of a possible five, gifting the one he did not take to the Italian contender Ivan Basso. Given that at the time Armstrong was on the point of sealing overall victory with two weeks left to race, such generosity was hardly the act of a man about to throw in the towel.

Few would disagree that in stage racing, cycling's best-known speciality and the one Armstrong has dominated since 1999, the Texan has nothing left to prove. But having managed to take six Tours - something not even the greatest cyclist ever, Eddy Merckx, could do - turning his hand to trying to win lesser races, where Armstrong has strangely always been much less adept, would smack of anticlimax at this point in his career.

This conundrum explains Armstrong's choice of sporting swansong: to take a seventh Tour this July, as he puts it, "in such a way that says in the minds of other people that I could have gone on to win again".

Should it happen, Armstrong will be the first Tour winner to make the event the last race of his career - the closest before was the French great Bernard Hinault, who took the Grand Boucle five times, then announced in 1986 before July that he would not be back for the Tour again. However, Hinault went on to take part in other races.

But for Armstrong, whose career after having cancer has centred purely around the Tour, a last yellow jersey in Paris would be a much more appropriate exit - and also one which would, in his mind at least, add that final, perfect touch to the myth of "the invincible Lance".

Much to the dismay of his rivals, who have had to put up with Armstrong's domination for the past six years, the Discovery Channel team leader seems to be taking his ideal career finish very seriously. After an uneven spring, when he failed for the first time in his career to clinch any pre-Tour wins, Armstrong's last warm-up race, the eight-day Dauphiné Libéré event in France, finally confirmed he was on track.

Fourth overall, Armstrong was a menacing presence throughout, never on the attack but demonstrating that his condition was as solid in the mountains, where he finished no lower than seventh on a stage, as it always has been. "What mark would I give myself? A B-plus - but then [four weeks before the Tour] maybe anything higher might not be so good," Armstrong reasoned afterwards.

In good shape and with his team focused on victory, the only discouraging news for Armstrong is that all of his potential rivals, bar the 2004 Tour of Italy winner Damiano Cunego, who has glandular fever, will be on the start line. In a sport where athletes are exceptionally vulnerable to illness, more absentees would be expected.

"It doesn't matter," insisted Merckx, a close friend and training partner of the Texan. "Barring accident, Armstrong will win again. I can't see anyone stopping him." Except, of course, Armstrong himself.