Team Astana's Alberto Contador wins on L'Alpe d'Huez but fails to escape from Janez Brajkovic (Team RadioShack) who keeps overall race lead.

Two-time Tour de France champion Alberto Contador has won the toughest stage of the Criterium du Dauphine Libere after beating race leader Janez Brajkovic in a two-man sprint.

Contador launched several attacks in the final ascent to L'Alpe D'Huez but Brajkovic responded to all of them.

With a strong head wind in the final stretch, Contador stayed on Brajkovic's wheel and overtook the RadioShack rider in the last 50 meters.

Brajkovic retained the overall lead.

Contador returned to competition at the Criterium after not racing since the Liege-Bastogne-Liege on April 25.

"I'm very touched to win at L'Alpe d'Huez," said Contador, who was gearing up for the Tour de France in the French Alps. "My team worked for this from the beginning of the stage. When you have the chance to win at the top of a hill everybody knows, you can't lose the opportunity."

The sixth stage covered 94.1 miles from Crolles to the famous ski resort and included two difficult climbs before the final L'Alpe d'Huez ascent, which features 21 curves.