Reigning Vuelta a Espana champion Primoz Roglic took the leader's red jersey on this year's race with an emphatic solo win on stage 17 on Wednesday.
The Jumbo-Visma rider, who broke away from the pack alongside Egan Bernal (Ineos) with 60km remaining, dropped the Colombian with 7.5km left to go solo up the climb and claim a third stage victory, 1:35 ahead of the chasers.
Bernal eventually finished the stage seventh after being caught by a chasing group, with Roglic's American team mate Sepp Kuss taking second spot.
The Slovenian race leader has a 2:22 advantage over second-placed Enric Mas (Movistar). Odd Christian Eiking (Intermarche-Wanty-Gobert Materiaux), who had been in red at the start of the day, crashed on a descent, finishing 9:20 back.
"It was a really impressive day. When Primoz went with Bernal, the pace before that was already really hard," Kuss said.
"It was a brave move to go that far out, but I could tell he really wanted to do something today and he did it an impressive way.
"Tomorrow there's another crazy hard climb and anything can happen - everyone will be tired after today."
Wednesday's vicious 186km stage contained four major climbs, starting with the third-category Altu de Hortigueru inside the first 40km.
It was on this first climb that an eight-man break was reeled in by the peloton as the rain began to pour down.
A large group of GC contenders remained together until the second ascent of the first-category Collada Llamena 60km from the end of the stage, when Bernal attacked and Roglic promptly followed.
The duo worked together until the early slopes of the hors-categorie Lagos de Codavonga climb before Roglic pulled away as the inclines reached 16%.
The race remains in the Asturian mountains on Thursday with another summit finish on the 162.6km course from Salas to the Alto d'el Gamoniteiru.