COURCHEVEL, France -- Lance Armstrong took a decisive step Tuesday toward a seventh consecutive Tour de France title, blowing away his main rivals in the first Alpine stage to regain the overall lead.
Armstrong did the damage on the punishing 13.8-mile climb to the ski station of Courchevel, eating up the ascent with ease while Jan Ullrich and other challengers grimaced in pain behind.
Spain's Alejandro Valverde won the 10th stage, just beating Armstrong to the finish line, but is not considered one of Armstrong's main rivals in this year's race. Valverde and Armstrong finished the 110.9-mile stage in 4 hours, 50 minutes, 35 seconds.
Mickael Rasmussen is second in the overall standings, 38 seconds behind Armstrong. Ivan Basso, among the main challengers left behind by Armstrong on Tuesday, is third overall -- 2:40 behind the Texan.
Rasmussen finished the stage in third place, 9 seconds behind Valverde and Armstrong.
Valverde and Armstrong shook hands in the saddle after they crossed the line together.
"Today, I had good legs," Armstrong said. "We are in a good position with regards to some of the main rivals, so we'll have to protect that."
His powerful ride silenced doubts that Armstrong is too old at 33, or too jaded after his record six victories, to win again. He is following the winning formula of previous years -- when Armstrong hammered rivals in the mountains, building up leads that carried him to victory in Paris.
Last year, Armstrong won all three Alpine stages and one of two in the Pyrenees.
Armstrong declined to claim that overall victory was his just yet. Two more stages await in the Alps, followed by the Pyrenees and a final time trial before the three-week race finishes in Paris on July 24.
"There's still a lot of racing to go," Armstrong said.
The American praised his Discovery Channel team, which piled on the pace in the first section of the ascent to whittle down the field, after struggling on a moderate climb last week.
Doubts had arisen whether the team could give the support that Armstrong needs in the Alps.
"It is a really tough team, with a lot of pride," Armstrong said.
He also praised Valverde, a 25-year-old racing his first Tour.
"Everybody has seen the future of cycling," Armstrong said. "He is a classy young rider."
Valverde was thrilled with the result.
"My dream was to win a stage, now that is done," said Valverde, who trails Armstrong by 3:16 overall. He said the Texan "looks as strong as he did in previous years."
Ullrich, the 1997 Tour winner and a five-time runner-up, placed 13th, 2:14 behind the leaders. The German trails Armstrong by 4:02 overall.
One of the biggest surprises was the collapse of Alexandre Vinokourov. Ullrich's teammate from Kazakhstan had been expected to seriously challenge Armstrong.
Vinokourov trailed in 5:18 behind Armstrong in 24th place. His overall deficit grew to 6:32.
Armstrong said he expects Ullrich and Vinokourov to bounce back.
"I don't think they are finished. I am going to be the last person to write them off," he said. "They are going to make life difficult and we'll continue to watch them and continue to respect them."
• Because of a protest at the start by farmers angry over wolf attacks on sheep and cows, organizers shortened the route by 8.7 miles, beginning the race just after the town of Froges, near the Alpine city of Grenoble.
That cut the run to the ski station of Courchevel to 110.9 miles instead of 119.6-miles. The route included two major climbs, including a long uphill finish, that were expected to show which of the main riders are on top form and start separating pretenders from genuine contenders.
• Russian Evgeni Petrov was expelled from the race before Tuesday's stage after he failed a blood test.
The Lampre cyclist was among 33 riders given a blood test Tuesday morning by cycling's governing body. All but Petrov were allowed to continue, organizers said.