Britain's Chris Froome won the 17th stage of the Vuelta a Espana after a thrilling final hill climb.
Froome, of Team Sky, edged out Spain's Juan Jose Cobo of Geox, who retained the overall leader's red jersey.
The one-second victory is the first mountain-top stage win by a Briton in a major since Robert Millar in the Tour de France in 1989.
"That was one of the hardest days on the bicycle in my life," said Froome.
"The hardest stages are now over but we'll still go out there in the final four days of the race and look to make it hard for Cobo," he added.
Froome, 26, trails Cobo by just 13 seconds in the overall standings with four stages to go.
The Kenya-born rider gained nine seconds on Cobo's lead in the overall standings through his one-second win and bonus points, setting up the prospect of a dramatic final four stages before the riders reach Madrid on Sunday.
Another British member of Team Sky, Bradley Wiggins, finished 12th in Wednesday's mountainous 211km stage from Faustino V to Pena Cabarga - the longest of this year's Tour.
Wiggins lost time on the overall leaders but retains third place overall.
The Olympic gold medalist, who is now one minute and 41 seconds behind Cobo overall, congratulated his teammate and commented on the hostile atmosphere on Twitter: "Chris Froome going from strength to strength, Superb. And all that after people shouting at him, "you win we kill you", unbelievable."
Froome showed dogged determination throughout a final stage in which the lead changed hands several times.
A duel between Froome and Cobo ended with the Briton crossing the line just one second ahead of the Spaniard to clinch his first victory in one of the Grand Tour events.
Dutchman Bauke Mollema of Rabobank was third, 21 seconds behind Froome.
Thursday's 18th stage takes the riders 174.6km from Solares to Noja, which should see Cobo and Froome resume their battle for the lead.
