Lance Armstrong (search) turned two treacherous and cobblestone stretches of the third stage to his advantage Tuesday while Spanish rival Ivan Mayo (search) crashed in a blow to his Tour de France (search) hopes.

Armstrong's U.S. Postal Service squad was ruthless, powering to the front of the speeding main pack of riders before hitting the first of the two bone-shaking, dangerous and dusty cobbled tracks on the 130-mile route.

The team safely shepherded the five-time champion across the obstacle. Other rivals, including 1997 Tour champion Jan Ullrich (search) and Tyler Hamilton (search) of the United States, also emerged unscathed.

But Mayo went down as teams were battling fiercely, juggling for position and riding almost flat out to place themselves at the front of the pack before it hit the bumpy stretch.

As Mayo, with a gaping tear in his shorts, struggled back to his feet, Armstrong and his U.S. Postal squad raced ahead. Mayo struggled to make up the lost time before the finish, but the damage was done. He lost a large chunk of time to Armstrong — a major setback in his bid to capture the three-week race.

Jean-Patrick Nazon of France won the stage from Waterloo in Belgium to Wasquehal in northern France.

The two cobblestone tracks weren't long — together totaling 2.4 miles. But they proved decisive. Armstrong had warned just a day earlier that the cobblestones could finish some riders' Tours. He was right.

Several other riders were caught in the crash that took down Mayo. They included Italian Marco Velo, who finished in a roadside ditch, his collarbone broken, his Tour over.

Mayo can still make up time in later mountain stages that are his specialty. But minutes are a big gap to fill. He risks losing yet more time to Armstrong on Wednesday, in a team time trial that the Postals won last year and are among the favorites to win again.

The cobblestones usually form part of the Paris-Roubaix race, a grueling classic known as "The Hell of the North." Not since 1985 had the Tour veered onto cobbles. Some teams and riders complained that they should not have been included in cycling's showcase race.

"Some people's Tour will be finished," he had said Monday. "I could be one of those people, and I'm not dumb enough to think that I couldn't be. And that would be a shame."

"But at the same time, the cobbles are a big part of French cycling," he added. "If you look at Paris-Roubaix, they are a beautiful thing, if you look at it like that, you should say they should be part of the Tour."