Laiseka's biggest win before this was at Luz Ardiden in 2001

Laiseka broke away from a group of five favourites 3km from the Pyrenean summit for the third stage win of his career.

Spaniard Carlos Sastre was 15 seconds behind in second while compatriot Roberto Heras was third.

Menchov finished fifth to stay ahead of Heras and Spaniard Francisco Mancebo in the overall standings.

"I had a real crisis earlier on the final climb, when Sastre attacked, but then I managed to pull it all back together again," said Laiseka, whose biggest win was at Luz Ardiden in 2001.

"I knew I wasn't going to be followed by the favourites for the overall, they'd be too busy watching each other. When it comes to winning, I'm still worth placing a bet on."

Tour of Spain Stage 11 results:
1. Roberto Laiseka (Spa/Euskaltel Euskadi) 5:09:38"
2. Carlos Sastre, (Spa/CSC) 15 seconds behind
3. Roberto Heras (Spa/Liberty Seguros) same time
4. Francisco Mancebo (Spa/Illes Balears) st
5. Denis Menchov (Rus/Rabobank) st
6. Carlos Garcia Quesada (Spa/Comunidad Valenciana) st
7. Miguel Angel Martin Perdiguero (Spa/Phonak) +55
8. Tom Danielson (US/Discovery Channel) same time
9. Manuel Beltran (Spa/Discovery Channel) st
10. Santos Gonzalez (Spa/Phonak) st

Overall standings
1. Denis Menchov (Rus/Rabobank) 45:07:35"
2. Roberto Heras (Spa/Liberty Seguros) 47 seconds behind
3. Francisco Mancebo (Spa/Illes Balears) 1:53
4. Carlos Sastre (Spa/CSC) 1:57
5. Carlos Garcia Quesada (Spa/Comunidad Valenciana) 3:31
6. Tom Danielson (US/Discovery Channel) 5:03
7. Manuel Beltran (Spa/Discovery Channel) 5:09
8. Juan Miguel Mercado (Spa/Discovery Channel) 5:45
9. Ruben Plaza (Spa/Comunidad Valenciana) 5:58
10. Michele Scarponi (Ita/Liberty Seguros) 6:37