Team Sky's Bradley Wiggins lost the overall lead of the Vuelta a Espana this afternoon as the Angliru proved a climb too far for the Brit.
Juan Cose Cobo (Geox-TMC), who started the day in fourth overall 55 seconds behind Wiggins, took the stage and the leader's red jersey after a brilliant performance on the mountains slopes that ramp up to 24%.
The Spaniard attacked with 6km to go, and crossed the line 48 seconds ahead of Wout Poels (Vacansoleil-DCM), Denis Menchov (Geox-TMC) and Britain's Chris Froome.
Wiggins finished 1-21 behind, so by virtue of his time gains Cobo now leads Froome by 20 seconds, with Wiggins at 48 seconds.
Even before Cobo broke clear, Froome once again worked tirelessly for Wiggins, and it wasn't long before defending champion Vincenzo Nibali (Liquigas), Dan Martin (Garmin-Cervelo) and Joaquim Rodriguez (Katusha) were dropped from the GC group.
However, the Sky duo could not respond when Cobo attacked, and their pace visibly slowed on the steeper sections.
At the same time, Cobo was putting more seconds into the chasers, although at 4km from the summit he only lead the Wiggins group by half a minute.
By now Wiggins was looking uncomfortable, and it was no surprise when he lost touch with Froome, Poels and Menchov towards the summit.
With a week until Madrid, there could still be a British winner, but Team Sky may be forced to reassess their GC options now that Froome - once again - is their best
Vuelta a Espana 2011: stage 15, Aviles to Angliru, 144km
1.Juan Jose Cobo (Spa) Geox-TMC in 4-01-55
2. Wout Poels (Ned)Vacansoleil-DCM at 48 sec
3. Denis Menchov (Rus)Geox-TMC
4. Chris Froome (GBr) Team Sky all at st
5. Bradley Wiggins (GBr) Team Sky at 1-21
6. Igor Anton (Spa) Euskaltel-Euskadi
7. Maxime Monfort (Bel) Leopard-Trek all at st
8. Joaquin Rodriguez (Spa)Katusha at 1-35
9. Sergey Lagutin (Uzb) Vacansoleil-DCM
10. Bauke Mollema (Ned) Rabobank all at st
General classification after stage 15
1. Juan Jose Cobo Acebo (Spa) Geox-TMC in 59-57-16
2. Chris Froome (GBr) Team Sky at 20 sec
3. Bradley Wiggins (GBr) Team Sky at 46 sec
4. Bauke Mollema (Ned) Rabobank at 1-36
5. Maxime Monfort (Bel) Leopard-Trek at 2-37
Menchov (Rus) Geox-TMC at 3-01
7. Jakob Fuglsang (Den) Leopard-Trek at 3-06
8. Vincenzo Nibali (Ita) Liquigas at 3-27
9. Jurgen Van Den Broeck (Bel) Omega Pharma-Lotto at 3-58
10. Wout Poels (Ned) Vacansoleil-DCM at 4-13
Vuelta a Espana 2011: Related links
Wiggins says he will give it 100 per cent to defend Vuelta lead
Vuelta tackles unknown mountain top finish today
Froome: "This lead is a big milestone"
Wiggins in Vuelta: "We're in an amazing position"
Dan Martin delighted with King of the Mountains jersey
Sky dominates in Vuelta a Espana
Martin delighted with first ever grand tour stage win
Wiggins: A fantastic finish
Interview: Wiggins looks ahead of crucial three days of Vuelta
Farrar taken to hospital after Vuelta crash
Arvesen quits Vuelta with crash injuries
Anton suffers again but Rodriguez becomes Spain's top contender
Wiggins pleased with strong ride in Spanish sierras
Cavendish abandons Vuelta a Espana
Vuelta a Espana 2011: Teams, riders, start list
Vuelta a Espana 2011: Who's riding?
Vuelta a Espana 2011 team list
Vuelta a Espana 2011
: Stage reports
Stage 14: Taaramae takes stage
Stage 13: Albasini wins as Wiggins holds on to lead
Stage 12: Sagan takes second 2011 Vuelta stage win
Stage 11: Wiggins takes overall lead as Moncoutie wins stage
Stage 10: Brit Froome moves into overall Vuelta lead after time trial
Stage nine: Martin wins as Wiggins moves further up GC
Stage eight: Rodriguez wins again to take overall lead
Stage seven: Kittel wins chaotic bunch sprint
Stage six: Sagan takes Vuelta stage win in controversial circumstances
Stage five: Rodriguez takes second win for Katusha but Chavanel holds on
Stage four: Moreno wins first mountain skirmish at Sierra Nevada
Stage three: Lastras solos to stage and takes red jersey
Stage two: Sutton grabs stage win to set things right for Sky
Stage one: Leopard-Trek win opening TTT to put Fuglsang in front
Vuelta a Espana 2011: Photo galleries
By Graham Watson
Stage 12 photo gallery
Stage 11 photo gallery
Stage 10 photo gallery
Stage nine photo gallery
Stage eight photo gallery
Stage seven photo gallery
Stage six photo gallery
Stage five photo gallery
Stage four photo gallery
Stage three photo gallery
Stage two photo gallery
Stage one photo gallery
Vuelta a Espana 2011: TV guide
Vuelta a Espana 2011: ITV4 TV schedule
Vuelta a Espana 2011: British Eurosport TV schedule
ITV to show 2011 Vuelta
Thank you for reading 20 articles this month* Join now for unlimited access
Enjoy your first month for just £1 / $1 / €1
*Read 5 free articles per month without a subscription
Join now for unlimited access
Try first month for just £1 / $1 / €1