BOURG-SAINT-MAURICE, France — Alberto Contador rode hard to keep the Tour de France's yellow jersey in the Alps yesterday, while teammate Lance Armstrong produced a dazzling burst of speed to remain in second place.

Mikel Astarloza of Spain won the 16th stage, a 99-mile route from the Swiss town of Martigny to Bourg-Saint-Maurice. Contador and Armstrong finished in the main pack behind Astarloza and other breakaway riders.

Contador, the 2007 Tour winner from Spain, fought off an attack led by brothers Andy and Frank Schleck of Luxembourg in the day's second big climb.

"We had expected (an attack) and I gave my maximum. I could resist but not without difficulty," Contador said. "I'm happy after this difficult day."

Astarloza, who rides on the Euskadi Euskaltel team, thrust his fists in the air and kissed his fingers as he crossed the line in 4 hours, 14 minutes, 20 seconds. He was six seconds ahead of French riders Sandy Casar and Pierrick Fedrigo. The three-week Tour ends Sunday in Paris.

With a little more than a mile to go yesterday, Astarloza escaped three other breakaway riders with him and held for his first Tour stage win.

"I was lucky to leave alone and finish alone," Astarloza said. "I'm a complete rider but I'm not good at the sprint, so I have to attack from far away. This is the biggest day of my career."

Contador, Armstrong, fourth-place Astana teammate Andreas Kloeden and third-place Bradley Wiggins of Britain all crossed 59 seconds after Astarloza.

Overall, Contador leads Armstrong by 1:37. Wiggins is third, 1:46 back, while Kloeden is 2:17 behind and Andy Schleck is fifth, trailing by 2:26.

With nearly 23 miles left, Andy Schleck attacked. He was quickly joined by Contador and a few other riders, but not Armstrong.

The 37-year-old Texan had dropped back by as much as 35 seconds. He then showed great speed to return to that small group of favorites, which included Schleck, Contador and Wiggins.

"I just didn't want follow that quick acceleration like I tried to do on Verbier" — the first Alpine stage on Sunday, Armstrong said. "I've stayed with the other group, and then I realized the race was basically going away from us.

"So, I had no choice other than trying to make the cross," Armstrong said. "So I waited until we had a steeper section and then I got away with an acceleration."

Contador was impressed.

"It's easy to explain — he's a very great rider," the Spaniard said. "He was in the past, and he showed it once again."

The course ended with a 19-mile downhill run. Downhills make it hard for breakaway riders to outpace the fast-moving pack.

Pope Benedict XVI sent greetings to Tour riders and organizers as the pack passed close to the Alpine retreat of Les Combes, overlooking Mont Blanc, where the pontiff is staying.