Vincenzo Nibali (Astana) hung onto the race leader's red jersey by just three seconds after being dropped by Chris Horner (Radioshack-Leopard) in the final kilometre of the steep climb to the finish on the Peña Cabarga.

Horner managed to distance the Italian on the steepest part of the climb, dancing on the pedals as he fight the 20% gradient and make Nibali suffer.

Horner finished sixth on the stage behind winner Vasil Kiryienka (Team Sky) and the remains of the break of the day. He gained 25 second gap on the Nibali, leaving him just three seconds behind the Italian on the general classification. Alejandro Valverde (Movistar) Joaquim Rodriguez (Katusha) both passed a struggling Nibali in sight of the line. They remain third and fourth overall at 1:09 and 2:24 respectively.

Kiryienka won the stage after being part of the break of the day and then attacking alone 40km out. He held off the chasers and the peloton, producing a huge effort to take a deserved victory. Chris Anker Sorensen (Saxo-Tinkoff) finished second, at 28 seconds after trying to chase down Kiryienka, with Adam Hansen (Lotto Belisol) third at 1:18.

Kiryienka movingly dedicated his win to Italy's Daniele Tortoli, his first directeur sportif, who died recently.

Nibali initially seemed strong enough to go with Horner when the American followed an attack by Rodriguez. However he went too deep and paid for his effort. With time bonuses of ten, six and four seconds award at stage finishes, and intermediate sprint time bonuses of six, four and two seconds available, the Vuelta is now finely balanced.

Horner could snatch the race lead on the finish to Alto Naranco at the end of Friday's stage or on the Angliru –the final climb of the 2013 Vuelta, on Saturday. The Vuelta ends in the centre of Madrid with a circuit stage on Sunday.

How it happened

Despite the steep finish to the stage overlooking the northern coastline, riders were keen to get in the break of the day, in the hope the overall contenders would let them stay away and they would have the legs to make it to the finish.

After some early attacks, the right move formed after 18km with 15 riders going away. In there were Egoi Martinez (Euskaltel-Euskadi), Simon Clarke (Orica-GreenEdge), Caleb Fairly (Garmin-Sharp), Angel Vicioso (Katusha), Adam Hansen (Lotto Belisol), Amets Txurruka (Caja Rural), Mickaël Chérel (Ag2r-La Mondiale), Reinardt Janse Van Rensburg (Argos Shimano), Vasil Kiryienka (Team Sky), Tiziano Dall'Antonia (Cannondale), Martin Kohler (BMC), Ben Gastauer (Ag2r-La Mondiale), Chris Anker Sorensen (Saxo-Tinkoff), Grega Bole (Vacansoleil-DCM) and Matteo Bono (Lampre-Merida).

Movistar and Cofidis missed the move and so initially took up the chase. However they quickly lost enthusiasm and sat up, allowing the gap to grow. Astana set the tempo for a while but the gap reached almost ten minutes after the first climb of Alto de Bocos and hit double digits before the Alto Estacas de Trueba after 100km of racing.

Amets Txurruka (Caja Rural) took the mountain points but the climb marked the point when the gap began to fall, with Movistar ready to do a lot of work to step up Valverde for the finale. However the hilly stage profile also offered an opportunity for attacks and the break split on the Alto del Caracol 40km from the finish.

Kiryienka attacks

Dall'Antonia, Bole, Bono, Gastauer and Fairly quickly lost contact but Kiryienka went on the attack, with Clark and Hansen. Kiryienka then went again, setting off on his lone adventure. He carved out a minute's lead and was on a mission to try and win the stage.

The other riders left in the break remained unorganised and unconvinced about chasing, often talking and even arguing about who should do the work. It all played into the hands of solo Kiryienka, with the quiet Belarus rider diving down the descents and perfectly pacing his effort on the climbs.

Movistar continued to set the pace all the way to the foot of the Peña Cabarga but as soon as the riders turned left and the gradient kicked in hard, Radioshack-Leopard took over. Nibali opened his red leader's jersey and glued himself to Horner's back wheel. He was on the defensive but seemed in control.

Nibali cracks

The pace remained hard but constant until the final two kilometres of the climb, when the gradient touched 20%. Suddenly Moreno and Rodriguez blew the race apart for Katusha but Horner had the strength to go with them. Nibali banged shoulders with Valverde on a corner as he fought to follow them. He got up to the trio at one point but had nothing left when Horner accelerated again in the final kilometre. His shoulders slumped as he fought for his breath but the Vuelta was escaping his grasp as Horner went out of sight.

The veteran American failed to snatch the lead by just three seconds but is perhaps now the favourite to win the Vuelta. We find out on Friday's finish to Alto Naranco and definitively on the Angliru finish on Saturday.

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