Michael Rasmussen took the overall leader's yellow jersey with a commanding victory in the eighth stage of the Tour de France.

Rasmussen, winner of the polka-dot climbers' jersey in the last two Tours, beat Spaniard Iban Mayo of the Saunier-Duval team on the arduous 165-km stage from Le Grand-Bornand to Tignes.

Mayo finished two minutes and 47 seconds behind the Rabobank rider with fellow Spaniard Alejandro Valverde taking third place for the Caisse d'Epargne team 3:12 off the pace.

Pre-race favourite Alexander Vinokourov of the Astana team ended the stage 4:29 behind Rasmussen after suffering on the last ascent of the day.

The Kazakh was beaten by a group of top contenders including Australian Cadel Evans, Luxemburg's Frank Schleck and Frenchman Christophe Moreau, who attacked eight times on the climb to Tignes.

Vinokourov, 22nd overall 5:23 behind Rasmussen, was unable to respond to Moreau's offensive and limited the damage thanks to super-domestique Andreas Kloeden, who helped him over the last three km of the final climb.

Both riders sustained injuries in separate crashes on Thursday and Kloeden is now 13th overall 3:46 behind Rasmussen.

'Today we had to try something. So I took my responsibilities,' said French champion Moreau. 'I was starting to get bored by this waiting game between the leaders.

'So I took a risk but I was not helped a lot by the others, let alone Valverde,' added Moreau, who won the prestigious Dauphine Libere stage race last month.

The AG2R rider attacked the main pack in the first hairpin of the ascent to Tignes, leaving Astana's Vinokourov and Kloeden and German Linus Gerdemann behind.

T-Mobile rider Gerdemann, who won Saturday's stage, was dropped 5km from the summit and lost his yellow jersey but remains second overall 43 seconds behind.

Mayo lies third overall 2:39 behind with the 27-year-old Valverde, who has yet to finish the Tour in his third participation, fourth 2:51 adrift.

An 18-man breakaway took shape after the category-three Col du Bouchet and the Rabobank team, counting on Rasmussen to bring a third consecutive polka-dot jersey back to Paris and Russian Denis Menchov for the overall standings, had to chase.

Going into the ascent of the category-one Cormet de Roselend, Rasmussen, who already had two Tour stage wins to his name, caught the peloton off guard and led a group of six, including T-Mobile's Australian Michael Rogers, to the summit with an advantage of 5:10 over the yellow jersey group.

The Australian crashed with David Arroyo on the descent. The Spaniard fell over the security barrier but both riders managed to get back on their bikes. Rogers, however, sustained a shoulder injury and pulled out in tears with 29km to go.

Compatriot Stuart O'Grady also retired with a back injury following a crash on the descent of the Cormet de Roselend.

Leading positions after Stage 8 Le-Grand-Bornand - Tignes (165km):
1 Michael Rasmussen (Den) Rabobank 4hrs 49mins 40secs
2 Iban Mayo Diez (Spa) Saunier Duval - Prodir at 2.47
3 Alejandro Valverde Belmonte (Spa) Caisse d'Epargne at 3.12
4 Christophe Moreau (Fra) AG2r Prevoyance at 3.13
5 Frank Schleck (Lux) Team CSC
6 Cadel Evans (Aus) Predictor – Lotto
7 Andrey Kashechkin (Kaz) Astana all at same time
8 Alberto Contador Velasco (Spa) Discovery Channel Pro Cycling Team at 3.31
9 Denis Menchov (Rus) Rabobank at 3.35
10 Carlos Sastre Candil (Spa) Team CSC at same time