Joaquim Rodriguez cut the deficit on leader Fabio Aru to just one second with victory in the 15th stage of the Vuelta a Espana.
The Spaniard stretched away from the pack with 1km left on the gruelling category one climb to the summit of Sotres Cabrales.
Poland's Rafal Majka (Tinkoff-Saxo) was 12 seconds adrift in second and Daniel Moreno (Katusha) third.
Italian Aru was fifth on the stage, 15 seconds behind.
Rodriguez might have claimed the red jersey himself if he had not decided to celebrate before crossing the finish line for his ninth Vuelta stage win.
Dutch danger man Tom Dumoulin (Giant) recovered valuable seconds in the last kilometre to trail Aru by 1min 25secs and remain in touch in third place overall with his favoured time trial coming after Tuesday's rest day.
Riders will be tested again in the mountains on Monday with the 185km stage between Luarca and Ermita de Alba Quiros.
The 21-stage Grand Tour finishes in Madrid on 13 September.
Stage 15 result:
1. Joaquim Rodriguez (Spa/Katusha) 4 hrs 33mins 31secs
2. Rafal Majka (Pol/Tinkoff - Saxo) +12secs
3. Daniel Moreno (Spa/Katusha) +14secs
4. Nairo Quintana (Col/Movistar) +15secs
5. Fabio Aru (Ita/Astana) same time
6. Mikel Landa (Spa/Astana) +18secs
7. Esteban Chaves (Col/Orica) +20secs
8. Mikel Nieve (Spa/Team Sky) +24secs
9. Alejandro Valverde (Spa/Movistar) +29secs
10. Domenico Pozzovivo (Ita/AG2R) +41secs
General classification after stage 15:
1. Fabio Aru (Ita/Astana) 61 hrs 53mins 56secs
2. Joaquim Rodriguez (Spa/Katusha) +1sec
3. Rafal Majka (Pol/Tinkoff - Saxo) +1min 24secs
4. Tom Dumoulin (Ned/Giant) +1min 25secs
5. Esteban Chaves (Col/Orica) +1min 34secs
6. Daniel Moreno (Spa/Katusha) +2mins 08secs
7. Mikel Nieve (Spa/Team Sky) +2mins 19secs
8. Alejandro Valverde (Spa/Movistar) +2mins 25secs
9. Nairo Quintana (Col/Movistar) +3mins
10. Louis Meintjes (SA/ Team MTN) +5mins 07secs