Sabero - Spain's Oscar Rodriguez, of the Euskadi team, stunned his peers to win the 13th stage of the Tour of Spain on Friday as compatriot Jesus Herrada (Cofidis) retained the leader's red jersey.
Poland's Rafal Majka (Bora) and Belgian Dylan Teuns (BMC) completed the podium after seeing Rodriguez coolly ride away from their leading group inside the final kilometre of the climb to La Camperona.
Herrada saw his lead over Britain's Sean Yates (Mitchelton) and Colombian Nairo Quintana (Movistar) cut to 1min 42 and 1:50 respectively, with Movistar veteran Alejandro Valverde, the 2009 champion, still in fourth at a further four seconds adrift.
But it was Rodriguez who left the biggest impression on the stage after a performance worthy of riders far more experienced earned him his biggest win to date, by far.
In what is his first season in the professional ranks, the 23-year-old kept his composure within an earlier breakaway of 30 riders before playing poker with his rivals on the 8.8 km climb to the summit finish, where the gradient of some sections was a gruelling 20%.
After Teuns and Majka had broken clear of the splintering chase group in the final kilometres, Rodriguez kept his cool before deciding to play catch-up.
With one kilometre to go, Rodriguez played his ace card to perfection, leaving Majka and Teuns in his wake on his way to securing his maiden professional win. Majka was second and 19secs behind.
The young Spaniard's previous best result was securing the mountains prize at the Tour of the Alps earlier this season.
Herrada, meanwhile, could struggle to maintain his lead through the weekend.
Having started the day with a 3:22 lead on Yates, the Spaniard will start Saturday's 14th stage with a 1:42 advantage on the Englishman.
The 14th stage will prove an even tougher test than Friday's stage. Held over 171 km between Cistierna and Les Praeres, it finishes with a final climb featuring gradients of 15%.
The 15th stage on Sunday is the third of three consecutive days in the mountains, a 178.2 km ride from Ribera de Arriba to Lagos de Covadonga.