Pena Cabarga - Britain's Chris Froome of Team Sky won the 17th stage of the Tour of Spain on Wednesday in a gruelling uphill duel to the finish line with Spain's Juan Jose Cobo, who retained the leader's red jersey.
The 26-year-old Kenya-born rider - the great revelation of this year's Tour - cut Cobo's lead in the overall standings by nine seconds through his hard-fought one-second win and bonus points.
He now trails the Geox cyclist by just 13 seconds, setting up the prospect of a thrilling 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 - and lost time on the overall leaders while retaining third place.
The 31-year-old Olympic gold medalist is now one minute, 41 seconds behing Cobo.
In the final hill climb in the 6.1kms up the Pena Cabarga, which has gradients that reach 19 percent, the lead changed hands several times as first Ireland's Daniel Martin then Belgium's Juergen van den Broeck attacked.
When a determined Froome took over, he seemed set to take the stage and possibly the leader's jersey before an exhausted Cobo appeared behind him.
A duel between the two ended with the Briton crossing the line just one second ahead of the Spaniard. Third was Dutchman Bauke Mollema of Rabobank, 21 seconds behind Froome, while Martin was fourth, three seconds further back.
"It was one of the toughest stages in my career," said Froome, who had held the leader's red jersey after the 10th stage. "Today, Juanjo (Cobo) was really strong."
The stage was marked by several short-lived breakaways.
Three Movistar riders - Spaniards Sergio Pardilla and David Lopez and Lithuania's Ignatas Konovalovas - withdrew from the event due to stomach upsets.
Thursday's 18th stage takes the riders 174.6kms from Solares to Noja, which should see Cobo and Froome resume their battle for the leadership.
Tour of Spain results after Wednesday's 17th stage, a 211km ride from Faustino V to Pena Cabarga:
1. Chris Froome (GBR/SKY) 4hr 52min 38sec
2. Juan Jose Cobo Acebo (ESP/GEO) at 1sec
3. Bauke Mollema (NED/RAB) 21
4. Daniel Martin (IRL/GRM) 24
5. Igor Anton (ESP/EUS) 27
6. Mikel Nieve (ESP/EUS) 27
7. Marzio Bruseghin (ITA/MOV) 29
8. Jurgen Van den Broeck (BEL/OLO) 31
9. Denis Menchov (RUS/GEO) 31
10. Benat Intxausti (ESP/MOV) 35
11. Daniel Moreno (ESP/KAT) 35
12. Bradley Wiggins (GBR/SKY) 39
13. Chris Anker Sorensen (DEN/SAX) 42
14. David Moncouti (FRA/COF) 49
15. Vincenzo Nibali (ITA/LIQ) 51
16. Serguey Lagutin (UZB/VAC) 54
17. Nicolas Roche (IRL/ALM) 1min 02.
18. Wout Poels (NED/VAC) 1:14.
19. Maxime Monfort (BEL/LEO) 1:22.
20. Christophe Le Mevel (FRA/GRM) 1:34.
1. Juan Jose Cobo Acebo (ESP/GEO) 69hr 31min 41sec
2. Chris Froome (GBR/SKY) at 13sec
3. Bradley Wiggins (GBR/SKY) 1min 41sec
4. Bauke Mollema (NED/RAB) 2:05.
5. Denis Menchov (RUS/GEO) 3:48.
6. Maxime Monfort (BEL/LEO) 4:13.
7. Vincenzo Nibali (ITA/LIQ) 4:31.
8. Jurgen Van den Broeck (BEL/OLO) 4:45.
9. Daniel Moreno (ESP/KAT) 5:20.
10. Mikel Nieve (ESP/EUS) 5:33.
11. Wout Poels (NED/VAC) 5:43.
12. Jakob Diemer Fuglsang (DEN/LEO) 5:50.
13. Chris Anker Sorensen (DEN/SAX) 7:06.
14. Daniel Martin (IRL/GRM) 7:22.
15. Serguey Lagutin (UZB/VAC) 8:57.
16. Marzio Bruseghin (ITA/MOV) 9:58.
17. Nicolas Roche (IRL/ALM) 10:31.
18. Kevin Seeldraeyers (BEL/QST) 10:50.
19. Carlos Sastre (ESP/GEO) 16:00.
20. Janez Brajkovic (SLO/RSH) 17:15.