Olympic champion Samuel Sanchez won the 12th stage of the Tour de France after a thrilling climax to the first mountain stage of this year's race.
Frenchman Thomas Voeckler, not a renowned climber, sprang a shock by retaining his yellow jersey.
Welshman Geraint Thomas led towards the end of the gruelling 211km trek, from Cugnaux to Luz Ardiden, before fading.
Jelle Vanendert was second ahead of Frank Schleck, who leapfrogged Cadel Evans into second overall.
He was 10 seconds behind the Belgian while his brother Andy - last year's runner up - is now up to fourth, 11 seconds behind Evans, after finishing sixth on Thursday.
Defending champion Alberto Contador, now seventh overall, struggled to an eighth-place finish in the Pyrenees - and now sits a full four minutes behind race leader Voeckler.
Euskaltel's Sanchez was seven seconds ahead of Belgium's Vanendert, who he attacked in the last of three climbs - considered some of the hardest in professional cycling - on the day's course.
Thomas, now Team Sky's leader after the withdrawal of injured Bradley Wiggins, fell off his bike twice before recovering to remain in contention until 7km from the finish, eventually finishing in 36th.
"I just slipped going round that first bend," he told ITV4.
"It wasn't mechanical, and the second one I had a bit of mud on the tyres. I lost my head a bit but we changed bikes and it was fine.
"At the start I just wanted to get stuck in and race it, and I did that. With seven kilometres to go I thought it was quite close, but there was still a lot of pedalling to go."
He held the white jersey for best young rider earlier in the Tour this year but FDJ's Arnold Jeannson of France has taken hold of it.
Britain's Mark Cavendish finished 153rd, more than 33 minutes adrift, while also picking up nine points in the race for the green jersey to extend his lead in that competition, while Spaniard Sanchez took the polka dot King of the Mountains jersey off Johnny Hoogerland.
STAGE 11 RESULT:
1. Samuel Sanchez (Spain / Euskaltel) 6 hrs 01 mins 15secs"
2. Jelle Vanendert (Belgium /Omega Pharma-Lotto) +7"
3. Frank Schleck (Luxembourg / Leopard) +10"
4. Ivan Basso (Italy / Liquigas) +30"
5. Cadel Evans (Australia / BMC Racing) same time
6. Andy Schleck (Luxembourg / Leopard) same time
7. Damiano Cunego (Italy / Lampre) +35"
8. Alberto Contador (Spain / Saxo Bank) +43"
9. Thomas Voeckler (France / Europcar) +50"
10. Pierre Rolland (France / Europcar) same time
1. Thomas Voeckler (France / Europcar) 51h 54m 44s"
2. Frank Schleck (Luxembourg / Leopard) +1:49"
3. Cadel Evans (Australia / BMC Racing) +2:06"
4. Andy Schleck (Luxembourg / Leopard) +2:17"
5. Ivan Basso (Italy / Liquigas) +3:16"
6. Damiano Cunego (Italy / Lampre) +3:22"
7. Alberto Contador (Spain / Saxo Bank) +4:00"
8. Samuel Sanchez (Spain / Euskaltel) +4:11"
9. Tom Danielson (U.S. / Garmin) +4:35"
10. Nicolas Roche (Ireland / AG2R) +4:57"