Spaniard Oscar Rodriguez pulled off the biggest win of his career by snatching victory in stage 13 at the Vuelta a Espana on Friday while compatriot Jesus Herrada retained the red jersey but saw his lead significantly trimmed by Briton Simon Yates.
Rodriguez, 23, is riding his first grand tour and is out of contract with his Euskadi-Murias team but he made his mark by freeing himself from a small breakaway group in the final stretch of the summit of the La Camperona mountain, battling against gradients of 24 percent.
Rodriguez finished 19 seconds ahead of runner-up Rafal Majka of Poland and half a minute clear of third-placed Dylan Teuns of Belgium.
BMC's Nicolas Roche finished 6:51 back in 54th, leaving the Irishman 38th in the general classification.
His cousin Dan Martin, riding for UAE Team Emirates, pulled out of the race on Monday to be with his wife, who is expecting the arrival of newborn twins.
Race leader Herrada struggled in the mountains after going for broke in Thursday's flat stage to lift the leader's red jersey from Yates, and his gap over the Briton was cut down from three minutes 22 seconds at the start of the stage to one minute 42 seconds.
Colombian Nairo Quintana finished the strongest of the general classification hopefuls to leapfrog his Movistar teammate Alejandro Valverde into third place, eight seconds behind Yates.
Friday's stage was the first of three consecutive summit finishes which will put the general classification hopefuls to the test and is likely to have a huge say in who wins the race overall.
Saturday's stage is a new, 171km route up the Praeres mountain containing five classified climbs and just shy of 3,000 metres of vertical climbing, while Sunday sees a visit to Lagos de Covadonga, an old favourite of the Vuelta.