Alberto Contador has held on to the red jersey and looks likely to claim victory in the Vuelta a Espana.
Joaquim Rodriguez and Alejandro Valverde both finished ahead of the SaxoBank rider in a gruelling mountain stage.
However, the Spaniard dug deep to retain a lead of 1m 14s over his rivals, which looks good enough to give him a second tour title.
Only a mechanical failure can deny Contador victory on the ride into Madrid tomorrow.
It is the first time that the 29-year-old has competed since his return from a two-year doping ban.
Team Sky's Chris Froome held onto fourth place in the overall standings.