La Mongie, France ? The mountains bring out the best in Lance Armstrong.

The Tour de France champion took a big step toward a record sixth straight crown Friday with a display of climbing in the Pyrenees that left contenders dazed.

Jan Ullrich, Tyler Hamilton, Iban Mayo and Roberto Heras saw their dreams of dethroning the Texan fade as Armstrong’s blue jersey disappeared into the distance on a punishing ascent to the La Mongie ski station.

Armstrong moved from sixth to second in the overall standings following a ride in which he was runner-up to stage winner Ivan Basso of Italy.

Armstrong is 5:24 behind France’s Thomas Voeckler, but Ullrich is the champion’s main challenger. Another Pyrenean stage will be run today, and the Alps and a final time trial still are to come before the July 25 finish.

“Jan’s not finished,” Armstrong said. “He starts slow, and he’s a tough guy who doesn’t give up. He might have taken one on the chin today, but he always comes back and is strong in the last week.”

Armstrong indeed is comfortable in these parts. The last time the Tour covered this route — in 2002 — Armstrong won both stages. Now, Armstrong’s rivals need to quickly find a way to unsettle the 32-year-old cycling great. Otherwise, another victory most likely awaits in Paris.

Armstrong was not going all out at the end of Friday’s 12th stage, content to let Basso win a stage for the first time in four Tours.

“It was a pleasure for me to let him win,” Armstrong said. “He was super-strong.”

Ullrich, abandoned in the eight-mile final ascent, finished 20th, a daunting 2 minutes, 30 seconds behind. The German, the 1997 winner and a five-time runner-up, was thrown off by a storm that doused riders as they ascended the first of two climbs.

Five-time Tour de France champion Lance Armstrong, surrounded by his U.S. Postal Service teammates, rides in pouring rain during the 12th stage of the Tour de France cycling race. Armstrong finished second in the race Friday between Castelsarrasin and La Mongie, France.

“It was a bad day,” he said. “I noticed at the first mountain I didn’t have good legs, and I was cold on the downhill. But I fought until the end. With good weather and good legs, maybe I can come back.”

His team manager, Walter Godefroot, said: “I don’t know what to say, it’s really an uppercut. … We’re groggy.”

Just 55 seconds behind before Friday’s stage, Ullrich now trails Armstrong by 3:37 overall — a possibly insurmountable margin. Last year, Armstrong beat Ullrich by just 61 seconds.

Baking sunshine followed by rain on the 122.7-mile trek from Castelsarrasin in southwest France played into Armstrong’s hands.

“First the heat, then the thunder, then the sun again,” Armstrong said. “For the overall standings it is great.”

A burst of speed by Armstrong’s teammates did initial damage on the final climb, leaving other riders flailing. Armstrong and Basso were alone during the last 1.2 miles, riding together to the line. Armstrong finished in the same time as Basso and earned 12 bonus seconds as runner-up.

“Armstrong is the strongest man on this Tour,” Basso said. “I think he’s still got gas in his tank.”

Hamilton, an American and former Armstrong teammate, was the first major rival to fall off the back of the pack. He finished 3:27 behind and trails Armstrong by 4:22 overall. He said a back injury from a crash last week prevented him from doing better.