Belgian Philippe Gilbert powered to victory on stage 12 of the Vuelta a Espana, while race leader Primoz Roglic retained the red jersey.
Deceuninck-Quick Step rider Gilbert, who was not selected for the Tour de France, broke away on the last of three steep third-category climbs before holding off the chasers during a dramatic descent into Bilbao.
Basque rider Alexander Aranburu (Caja Rural) finished the 171.4km route three seconds behind in second spot, pipping third-placed Fernando Barcelo (Euskadi-Murias) on the line.
Roglic (Jumbo-Visma) and his title rivals crossed among the peloton, three minutes and two seconds adrift of Gilbert.
The Slovenian remains a minute and 52 seconds ahead of Spaniard Alejandro Valverde (Movistar) at the top of the general classification.
Gilbert, 37, celebrating his sixth Vuelta stage win, told Eurosport: "It was crazy. The atmosphere on the last climb it was really like in the classics, with all the flags and everything. It was really nice and they gave me a lot of motivation.
"I have been racing a lot here in the Basque country. I never had success so for me it's the first time and I am happy because I think Basque country is almost like Flanders, they love cycling here.
"It's also special because this is my 10th victory on a stage race on a grand tour, so it's a nice number."
Stage 13's 166.4km route includes seven mountain passes, climaxing with a hill climb to the top of Los Machucos.
Ireland's Sam Bennett (Bora-Hansgrohe) finished second from last on a stage that was never going to play to his strengths and now lies in 157th place in the 165-strong field.
Nicolas Roche, who was forced to abandon the Vuelta after a heavy crash on stage six, will be sidelined for some time after tests revealed he had suffered a fractured left patella.