Spain's Oscar Rodriguez produced a stunning final climb to win stage 13 of the Vuelta a Espana.
The 23-year-old, who rides for the Euskadi-Basque team but does not have a contract for next season, overtook Rafal Majka and Dylan Teuns late on a brutal climb which peaked at 24%.
Nairo Quintana of Movistar was the first home of the overall contenders, six seconds ahead of Simon Yates.
The Briton cut Jesus Herrada's overall lead to one minute 42 seconds.
Herrada had started the day three minutes 32 seconds ahead but struggled in the mountains after going for broke in Thursday's flat stage to take the leader's red jersey from Yates.
Colombian Quintana's performance saw him leapfrog Movistar team-mate Alejandro Valverde into third place, eight seconds behind Yates.
Friday's stage was the first of three consecutive summit finishes, a run that is likely to have a huge say in who wins the race.
Saturday's stage is a 171km route up the Praeres mountain containing five classified climbs and just shy of 3,000m of vertical climbing, while Sunday sees a visit to Vuelta favourite Lagos de Covadonga.
Stage six results:
1. Oscar Rodriguez (Spa/Euskadi Basque Country-Murias) 4hrs 17mins 05secs
2. Rafal Majka (Pol/BORA-hansgrohe) +19secs
3. Dylan Teuns (Bel/BMC Racing Team) +30secs
4. Bjorg Lambrecht (Bel/Lotto-Soudal) +38secs
5. Laurens de Plus (Bel/Quick-Step Floors) +43secs
6. Merhawi Kudus (Eri/Team Dimension Data) +1min 00secs
7. Ilnur Zakarin (Rus/Team Katusha-Alpecin) +1min 12secs
8. Pieter Serry (Bel/Quick-Step Floors) +1min 21secs
9. Edward Ravasi (Ita/UAE Team Emirates) +1min 25secs
10. Benjamin King (USA/Team Dimension Data) +1min 27secs
1. Jesus Herrada (Spa/Cofidis) 54hrs 50mins 19secs
2. Simon Yates (GB/Mitchelton-Scott) +1min 42secs
3. Nairo Quintana (Col/Movistar) +1min 50secs
4. Alejandro Valverde (Spa/Movistar) +1min 54secs
5. Miguel Angel Lopez (Col/Astana) +2mins 23secs
6. Rigoberto Uran (Col/Team EF Education First-Drapac) +2mins 33secs
7. Ion Izagirre (Spa/Bahrain-Merida) +2mins 35secs
8. Tony Gallopin (Fra/AG2R La Mondiale) +2mins 40secs
9. Steven Kruijswijk (Ned/Team LottoNL-Jumbo) +2mins 44secs
10. Emanuel Buchmann (Ger/BORA-hansgrohe) +2mins 47secs