Chris Horner extended his overall lead in the Vuelta a Espana after winning a dramatic battle with nearest rival Vincenzo Nibali during a brutal finish to the penultimate stage.

American Horner finished second on stage 20 behind France's Kenny Elissonde, who battled through large crowds on the fearsome Alto de L'Angliru to win by 26 seconds.

Nibali had attempted to claw back his three-second deficit to Horner by launching several attacks in the closing stages, but Horner refused to panic and patiently worked his way back to the Giro D’Italia winner each time.

And in the end it was RadioShack's Horner who was able to pull away through the dense fog to finish 28 seconds ahead of Alejandro Valverde in third, with Nibali given the same time in fourth.

With the addition of time bonuses, Horner now has a 37-second advantage over Nibali going into Sunday’s final stage, a largely ceremonial 109.6 kilometres from Leganes to Madrid.

Valverde is third overall, one minute and 36 seconds behind Horner, with Ireland's Nicolas Roche in fifth.

Roche finished the stage in 19th position, coming in three minutes and 42 seconds behind Elissonde.