Great Britain's Chris Froome reduced the gap on 2011 Vuelta a Espana leader Juan Jose Cobo with a stage win on the final summit finish of the route earlier today.

Froome attacked from a group of some six favourites around 1.2 kms from the finish on the short but steep climb of Pena Cabarga that concluded stage 17.

Cobo was dropped twice but he regained contact both times before Froome finally darted past his arch-rival within sight of the line to take the first Grand Tour stage win and second professional victory of his career.

Cobo was second behind the Team Sky rider, one second back, with Dutchman Bauke Mollema third, 21 seconds down.

With four days of the race remaining, Froome has squeezed Cobo's overall lead down to 13 seconds. Froome's British team mate Bradley Wiggins remains in third, one minute 41 seconds behind, according to provisional results.

So exhausted that he slumped against the barriers for several minutes, Froome later told reporters: "I'd watched the finish from last year on TV and I knew that last kilometre was so difficult it would be incredibly decisive."

"With 800 metres to go I'd got an initial gap and I thought I'd held him (Cobo) off but with 100 metres to go he came back again. Just when I thought Cobo would win the stage, I just managed to get past him for the victory."

Cobo, nicknamed 'the Bison of La Pesa' because of his stocky build and born in the Cantabria region where the stage was held, said that when Froome attacked he thought he would not be able to respond.

"I seriously thought I'd lost the Tour of Spain," Cobo told reporters. "I eased up and finally could recover, but the last kilometre went on forever."

Hundreds of Cobo supporters, many dressed up as bison to honour their hero, cheered the 30-year-old Geox rider as he strode on to the podium.

"If it hadn't been for all this support, I'd have lost the lead for sure," Cobo said. "I live close by, but I made a big mistake not coming to check out the finish of this stage beforehand."

Froome said that with such a tiny margin between himself and Cobo the battle for overall victory was not finished.

"It's probably going to come down to the bonus seconds on offer on each stage," he said. "But I'll go on fighting all the way to Madrid."

The 2011 Vuelta a Espana finishes in Madrid on September 11.

Watch Vuelta a Espana video highlights from all stages of the Vuelta a Espana 2011 in our video section.