The Texan started slowly on a course littered with technical difficulties that included a third category climb 15.5km from the finish. He was an unexpected seven seconds behind the overall runner-up, the Italian Ivan Basso, at the first intermediate checkpoint, and the time lag briefly fuelled speculation that cracks could finally be appearing in the 33-year-old's armour.
But as the Discovery Channel rider warmed to his task, the early delay proved to be a mere glitch en route to the 22nd stage win of his career. Halfway along the course, Armstrong had an advantage of 32 seconds over Ullrich, while Basso, after his powerful start, had cracked almost completely.
The American had checked the entire course twice in the morning, once on his bike and once in the team car and the attention to detail paid off in full. Negotiating the descents - dangerously sticky as tarmac melted in warm weather - with care but accelerating remorselessly on each of the lengthy technical sections, the Texan maintained his advantage before easing slightly at the finish. Taking no risks, he eventually crossed the line displaying his usual mirthless grin of maximum effort for one final time in his career.
For Armstrong, rather like this seventh Tour itself, victory was no more than the icing on the cake of his career. Twelve months ago he had already become the first rider in history to take the Tour six times, but his contract with Discovery Channel, his new team sponsor in 2005, specified he race one last Tour. On 18 April he announced he would retire after this year's event, then the Armstrong template - as his meticulous, almost manic preparation programme is known - swung into action.
He has been dominant throughout this year's Tour, but had failed, however, to take an individual stage in any event this season prior to yesterday's victory. With his children waiting for him at the finish line, Armstrong reflected that: "It's a dream come true being able to win in front of them".
"Winning [this stage] was not essential, but it was essential for me to prove why I deserved to have the yellow jersey."
If Armstrong was as untouchable yesterday as he has been throughout his career, Ullrich was able, thanks to his consistent if unspectacular performance in the final time trial, to secure a major consolation prize - third overall in Paris. The German's rival for the podium, the Dane Mickael Rasmussen, had an abysmal ride.
The Rabobank rider was forced to change his bike no fewer than three times because of mechanical problems, and if that was not enough, took two tumbles on the technical course. With his morale in tatters, Rasmussen finished 77th on the stage, sliding to sixth overall, with Ullrich benefiting the most.
All that remains for Armstrong today is a triumphant ride into Paris, listening to the American national anthem on the Champs Elysées as he dons his last yellow jersey, and then celebrations in the Ritz.
How hemaintains the motivation necessary to succeed in one of sport's most gruelling events remains a mystery. Speaking after the stage win yesterday he said he would leave the race with no regrets. "I know my time is up and I'm more convinced now than I have ever been that it was time to leave," he said. "There was no pressure for this victory, the only pressure was something within myself and wanting to go out on top."
Asked if he would win in 2006 had he not decided to retire, he said: "It would not be fair to say. My advantage over Basso is 4 mins 40 secs. That's a good time cushion, but at 34 I might take a big step down and somebody might take a big step up." There can be no doubt that Armstrong finishes his career as he wanted to, leaving on a high and with a record in cycling's blue riband event that will prove hard, if not impossible, to match.
"My condition is probably the best it could have been." he said - and recent data shows that Armstrong in fact was stronger physically this year than he was in 1999.
"Everybody's looking for the next Lance, but there won't be another one like him in a century," his loyal friend and team-mate, George Hincapie predicted recently. Whatever the case, Armstrong is quitting as he wanted - ahead of the game and with no doubts as to his crushing superiority.Reuse content