On stage 16, the riders must negotiate the legendary quartet of Col de Peyresourde, Col d'Aspin, Col du Tourmalet and Col d'Aubisque on a 196km ride from Bagneres-du-Luchon to Pau.

BBC: Pyrenees will star in 2010 Tour

On Col d' Agnes, 45km from the finish, Luxembourg's Andy Schleck also tried to spring free but the Astana team, a permanent fixture at the front of the pack, reacted instantly and ensured their two big stars stayed out of danger.

BBC: Sanchez secures stage eight win

Along with Casar, Efimkin and Mikel Astarloza, he had made a decisive break on the final climb, up the Col d'Agnes, then held off the peloton on a long descent to the finish line and fighting it out for the stage win.

BBC: Sanchez secures stage eight win