The seven-time champion, written off by most of the cycling experts before the race started i0n Monaco, went within a whisker of taking the yellow leader's jersey from Fabian Cancellara after the impressive collective triumph of his Astana team in Tuesday's team time trial.

A day after surging in a key breakaway to gain valuable time over his rival and teammate Alberto Contador, Armstrong moved up from third place to second overall _ he only trails race leader Cancellara of Switzerland by a few hundredths of second following the fourth stage after erasing a 40 second margin.

"That's the way it is. We did our best. At one point, we thought we had it (the yellow jersey), but if I look back on our performance ... we were as sound as we could be," Armstrong said. "I have no regrets. I don't look at that and lose sleep or get disappointed. That's when they stopped the clock. This is a long race, maybe there's one (yellow jersey) in my future."

Astana was timed in 46 minutes, 29 seconds for the 39-kilometer (24.2-mile) ride in and around Montpellier. That was 18 seconds better than Garmin, with Saxo Bank third, 40 seconds behind.

Armstrong and Cancellara share an overall time of 10 hours, 38 minutes, 7 seconds, although the Swiss rider was deemed a fraction ahead. Organizers examined Saturday's opening time trial in Monaco that was won by Cancellara. Those results were calculated to the thousandth of a second.

"That's Swiss timing," Cancellara said, laughing. "Time is on my side."

On roads sometimes very tight on the outskirts of Montpellier, Armstrong took long relays and was always in front to guide his teammates when the course was dangerous. It was reminiscent of Armstrong's dominance in the team time trial discipline at the US Postal and Discovery Channel teams for the last three years of his run of victories from 1999 to 2005.

"Well, what can I say? The team was simply awesome today. Consistent, fluid, mistake-free. We love this event (TTT) and are stoked to win," Armstrong noted in his Twitter account. "Popo and Klodi were on fire," he added, referring to teammates Yaroslav Popovych of Ukraine, and German Andreas Kloeden. "And they might need to repair the pavement on the sections where Alberto was pulling."

At the Astana bus just after the stage, it was time for celebration. Armstrong hugged all of his teammates as a swarm of reporters gathered, prompting police to intervene to secure a path to the podium for the seven-time Tour champion and his colleagues.

Even Contador, who is said to have a strained relationship with Armstrong, was rejoicing at the win.

"I think that today we have to be very, very happy," he said. "We have distanced enough riders like (Carlos) Sastre, (Cadel) Evans, (Denis) Menchov and even the Schlecks (Andy and Frank). It's a pity we missed the yellow jersey. You always like to have it, especially Lance, with all it means for him."

Astana's performance dealt a blow to several title hopefuls. Defending champion Sastre is 2:44 back; two-time runner-up Cadel Evans, whose team didn't preview the time trial and had a catastrophic run marred by a crash, is 2:59 behind and Menchov is 3:52 back.

"OK it's nice to win the stage, but I think today, the Tour de France is finished for some riders _ and we won't go into names ... ," said Armstrong. "With no disrespect, it's difficult to make up that time."

With Evans and Sastre potentially out of contention, the potential rivalry of Armstrong and the 26-year-old Contador, who won the 2007 Tour, is set to reach a new peak in the daunting Pyrenean summits.

Armstrong will face a tough test in the mountains. After Friday's trek between Barcelona and Arcalis _ the most demanding Pyrenean stage with a grueling final ascent _ Armstrong's rivals will know if the Texan still has the legs of his heyday. And Contador, the best climber in the world, will see if he still has a chance to knock Armstrong from his throne, at least within the Astana team.

During the team time trial, the two men collaborated well and shared a common objective.

"My point was to Alberto, 'Look, let's ride perfect, and make this race almost impossible to win for others,'" Armstrong said. "And I think we can say that we accomplished that."

After Cancellara, the next four riders are from Astana: Armstrong, with the same time; Contador, 19 seconds back in third; 2004 runner-up Kloeden is fourth, 23 seconds back; and Levi Leipheimer of the United States is fifth, 31 seconds behind.

Before the Pyrenees, Armstrong's team will be glad not to have to defend the yellow jersey. Wednesday's fifth stage is a 196.5-kilometer (122-mile) ride along the Mediterranean from Le Cap d'Agde to Perpignan that could favor breakaways if the wind blows. Cancellara's team will have to chase the potential fugitives while Astana could save forces for the mountain passes looming ahead.

Armstrong said he's "realistic" about his chance of victory when riders reach the Champs-Elysees in Paris on July 26.

"It's not going to be easy _ I'm not going to get last _ but it won't be like 2004, 2005, 2001," he said. "It's going to be a helluva lot harder than I expected. That's as honest as I can say it."

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Associated Press Writer Jamey Keaten contributed to this report.