The race organisation is clearly hoping for a repeat of last year's penultimate day cliff-hanger on the Angliru, where Chris Horner managed to fend of Vincenzo Nibali's last-ditch offensive. Today's climbs get progressively tougher, culminating in the Vuelta's first ascent of the stunning Ancares by its most difficult side, via Pan do Zarco.
Averaging 11 per cent for the first eight of the 12 kilometres, there are frequent ramps where featherweight climbers such as Nairo Quintana and Joaquim Rodríguez will be in their element. The grade eases towards the top before a tough final kilometre.
Today's winner will also be awarded the José María Jiménez Trophy, in tribute to the great Spanish climber who died a decade ago.
Javier Guillén says: "This isn't the toughest mountain stage. I think the Farrapona is what you'd call the 'queen' stage. But because this is the penultimate day and we are tackling the Ancares via its hardest Pan do Zarco route, it could be more decisive than the Farrapona."