Russian Denis Menchov's hopes of winning the Tour de France suffered a blow when he lost ground in the 16th stage, a 157-km mountain ride won by Frenchman Cyril Dessel yesterday.

Rabobank's Menchov was dropped by the other favourites on the descent of the Cime de la Bonette-Restefond, the roof of the Tour at 2,802 metres, and lost 35 seconds to his rivals. He dropped down to fifth place overall, 73 seconds behind the leader.

Frank Schleck, of Luxembourg, retained the overall leader's yellow jersey and leads Austrian Bernhard Kohl by seven seconds and Australian Cadel Evans by eight.

AG2r-La Mondiale rider Dessel beat compatriot Sandy Casar, of the Francaise des Jeux, with Spain's David Arroyo, of the Caisse d'Epargne, team in third.

"Little by little, in the ascent to La Bonette, I started to believe in victory," said Dessel.

"At the beginning I was working for my leader, Tadej Valjavec, because we wanted to catch (Stefan) Schumacher. But then I took my chance in the downhill."

American Christian Vande Velde, who started the stage fifth overall, lost all hope when he tired badly and trailed home with a 4:03 deficit.

France's Samuel Dumoulin, Thomas Voeckler and Christophe Le Mevel, with Belgian Sebastien Rosseler and German Schumacher, broke away after 40 km.

Schumacher upped the pace in the out-of-category ascent to the Col de la Lombarde, dropping his fellow breakaways one by one to open up a 12-minute lead over the peloton.

A chasing group led by Damiano Cunego and Dessel were some six minutes behind at the summit.