Armstrong endured arguably his worst day of his career on the world's biggest bike race after he crashed several times on the eighth stage to finish over almost 12 minutes adrift at the summit of Avoriaz in the French Alps.
Ahead of the race's first rest day, when his RadioShack team manager Johan Bruyneel is likely to hand the leader's torch to Levi Leipheimer, the seven-time champion is now in 39th place overall at 13:26 behind new race leader Cadel Evans of Australia.
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Cancer survivor Armstrong came into his final Tour campaign hoping to challenge reigning champion Alberto Contador for the race's coveted yellow jersey, albeit under a cloud of suspicion following the publication of allegations by former teammate Floyd Landis that Armstrong was involved in systematic doing while at their old team, US Postal.
Instead, the American was left with the also-rans for the final two climbs of the race -- and is now uncertain to continue.
"It's sad to see, but that's sport," said Bruyneel, the Belgian who helped spearhead Armstrong's competitive return to the sport after he successfully battled testicular cancer in 1998.
"There's a time for everything. He's been beaten by bad luck more than any physical deficiency. It's certainly the end of his aspirations to win the Tour de France."
Bruyneel played down suggestions that Landis's allegations had put extra pressure on Armstrong.
"That's got nothing to do with it," said Bryneel.
"He had a setback at the start of the stage when he almost crashed trying to avoid a fall in front of him, then 10km before the climb to (the Col de) Ramaz he had quite a heavy crash.
"Once he was on the Ramaz he was in difficulty. On the last climb (to Avoriaz) he told me he'd taken quite a big knock to his hip, and that it was impossible to produce the power he needed to make it back.
"Once he was behind and he had no chance of coming back, he effectively threw in the towel."
In between the Ramaz and Avoriaz, Armstrong fell again when two Euskaltel riders tumbled in front of him as they crested the easy, category three climb at Les Gets.
After the American's setbacks on stage three's ride over the cobbles to Arenberg, where he suffered a puncture and lost time to all his rivals, Bruyneel said it couldn't have been a worst first week.
"Everything that could have gone wrong went wrong. It started on the cobblestones, we had some bad luck that day when Lance suffered punctures and lost time," added the Belgian.
He said RadioShack, whose best placed rider is now Leipheimer in eighth overall at 2:14 behind Evans, will now have to readjust their ambitions for the race.
"Let's look and see during the rest day how Lance's injuries are, and how everyone else is and then we can adapt our strategies and objectives for the rest of the race."
