Italian Fabio Aru is on the verge of sealing his first Grand Tour win after he moved into the lead of Spain's Vuelta with just the parade around Madrid to come.
Spain's Ruben Plaza won the 175.8km stage from San Lorenzo de El Escorial to Cercedilla thanks to a remarkable solo breakaway ride from 114km out, ahead of Portugal's Jose Goncalves and Italian Alessandro de Marchi respectively.
Aru started the day six seconds behind Tom Dumoulin, but the Dutch rider finally cracked on the four category one climbs on the penultimate stage as his hopes of even a place on the podium were ended as he slipped down to sixth.
Spain's Joaquim Rodriguez and Poland's Rafal Majka look set to complete the podium in second and third respectively.
Aru finished second at the Giro d'Italia earlier this year and had been given the freedom to lead his Astana team once Vincenzo Nibali had been disqualified for being towed by a team car on stage two.
"This victory is for my team, it's not just about me. All the Vuelta they have been working very hard," he said.
"(Dario) Cataldo, (Mikel) Landa, Luis Leon Sanchez have given everything. We started this Vuelta with our difficulties, but we worked to be united. We motivated each other all the time, and that gave us strength.
"The public enjoyed a great battle. Even though I was tired, I gave my best. Sometimes you win, sometimes the results don't come your way, but you just have to keep fighting and that is what I have done.
Aru was well-flanked by his Astana teammates as Dumoulin's inability to stay with the stronger climbers was finally exposed on the penultimate climb of the stage up the Puerto de la Morcuera as he finished nearly four minutes down on Aru.
"At the moment, it's just disappointment. Tomorrow I will be proud, but now it's just disappointment," said Dumoulin.
"I was just empty. I had no legs. I had an idea but you have just got to deal with it. The whole race has been nice for me."
Nairo Quintana also pushed on the final two climbs as the fight for spots on the podium heated up, but the Colombian will have to settle for fourth as he failed to make up sufficient time on Majka or Rodriguez.
Quintana's Movistar teammate Alejandro Valverde endured a tough day as he finished alongside Dumoulin to lie seventh in the overall standings.