The battle for the red jersey is certain to heat up today. The stage mixes some renowned landmarks with new terrain. Chief among the former is the first pass of the day, the Collada de la Hoz. This was where Alberto Contador launched the stinging surprise attack that carried him to the overall title in 2012 at Joaquim Rodríguez's expense. The cat 1 San Glorio pass is long and sapping but there's plenty of time for the riders to recuperate before the final test, the cat 1 La Camperona.

The 10km climb starts easily enough but takes off over its final 3km, which averages 14 per cent. Several ramps are far more severe than that, up to 24 per cent in places, which will suit the pure climbers such as Contador and Nairo Quintana.

José Azevedo says: "A key day as it's the first of a series of three summit finishes. There are 40-odd kilometres after the cat 1 climb, so the gc riders will hold back to the final climb, which is very steep. If you don't have good legs here you won't be able to hide it."