One by one, the riders who are considered contenders to unseat six-time Tour de France champion Lance Armstrong cracked on the climb to this ski resort Tuesday, littering the roadway behind him like loose rock.

Three riders stayed with Armstrong in the final few miles, and his trademark acceleration in the final half-mile couldn't quite shake bright young Spanish star Alejandro Valverde, 25, who won the stage.

It may be a bit premature to declare this Tour de France over, but few men with the talent or the team support to chase Armstrong remain within realistic striking distance, and the yellow jersey he pulled on again Tuesday after a two-day hiatus is most likely what he will wear for his curtain call on the Champs-Elysees in 12 days.

Although Armstrong won't say so, the fiercest battling left in the race promises to be for the two other steps on the podium.

"Now we're in a good position with regards to some of the main rivals," Armstrong said. "We'll have to protect that and protect the jersey. Hopefully I'll retire in it.

"There's a lot of racing to go. . . . We'll try to race smart."

His observations were distinctly understated, given the fact that the T-Mobile team's triple threat of Germans Jan Ullrich and Andreas Kloden and Kazakh rider Alexandre Vinokourov dissolved. CSC's Ivan Basso, a good climber but a so-so performer in the time trials, trails Armstrong by 2 minutes 40 seconds.

The man closest to Armstrong is Danish rider Mickael Rasmussen of the Dutch Rabobank team, who is 38 seconds behind. Rasmussen won Sunday's Stage 9 on a long solo breakaway and stayed with the final four riders Tuesday until Armstrong and Valverde sprinted away near the finish.

"This is a totally new situation for me," said Rasmussen, whose only goal going into the Tour was to win the polka-dot climber's jersey. Armstrong said Rasmussen would have to be watched -- "No more seven-minute breakaways," he said -- but the former world mountain bike champion probably isn't harboring any illusions about bumping Armstrong out of first place.

Rasmussen doesn't do well against the stopwatch and finished more than three minutes behind Armstrong in the Stage 1 time trial. His team doesn't have the depth to support him the way Discovery backs Armstrong.

In what must be a numbingly familiar scenario to Armstrong's opponents, Discovery led the peloton with a vigorous pace through a valley up to the base of Courchevel.

His teammates took their usual efficient turns setting the pace and peeling off when they were out of gas. The last man left with Armstrong was promising 25-year-old Ukranian rider Yaroslav Popovych, who may inherit the mantle of team leader next year.

Popovych crashed in the descent of the Cormet de Roselend, the penultimate climb of the day, and had to have his rear wheel changed but seemed fresh and powerful as he accompanied Armstrong up to Courchevel.

"I don't know if he's a future Tour de France winner, but he's definitely a very good bike rider," Discovery Team Director Johan Bruyneel said. "He's good on the time trials and he's good in the mountains. He's smart and he's a hard worker."

Top riders began crumbling early in the 13.7-mile ascent. Perhaps the most startling sight was the seemingly always composed Vinokourov suddenly laboring and falling off the lead group with his mouth and his jersey hanging open.

Vinokourov finished more than five minutes back and is 6:32 behind Armstrong in the overall standings. His teammates Ullrich and Kloden towed each other up the hill after being dropped and are both more than four minutes off the pace.

Some team leaders limited the damage and managed to maintain or improve their chances at the podium. Christophe Moreau of the Credit Agricole team is fourth, 2:42 behind Armstrong and striving to be the first French rider to finish in the top three since Richard Virenque was second in 1997.

Gerolsteiner leader Levi Leipheimer, who has talked openly about his podium ambitions, persevered to cross the line alone in sixth place Tuesday, 1:15 behind Armstrong and Valverde, and is also in sixth place overall.

Valverde vaulted to fifth in the standings and further brightened a resume that includes a silver medal and a fifth-place finish in the world championships and a stage win at the Paris-Nice race this year. But he insisted he will ride for his teammate Francisco Mancebo, who was also in the lead quartet on the last brutal climb.

"Now we have to stick together as a team," Valverde said. "Lance demonstrated today that he is as strong as ever. All I was thinking about was trying to stay on his wheel."

Armstrong admitted he was surprised at Valverde's staying power.

"I'm not blowing smoke -- he could be the future of cycling," Armstrong said. "He's a complete rider, a smart rider, a patient rider, on a good team surrounded by good people. He's been good from the first day he showed up. All he'd have to work on in this race is his time trialing, and I expect he'll do that."

Lance Armstrong returns to the overall lead in Tour de France with a second-place finish in Stage 10.