Ben O'Connor finishes the second week of the Vuelta a España in the red jersey after defending himself well in Cuitu Negru. Enric Mas and Primoz Roglic were strong on the day but the gaps were not huge; as Pablo Castrillo won stage 15 - his second of the week.
The stage had a very fast start and it took a long time for a breakaway to be formed in the 143-kilometer day. 20 riders are there ultimately including three UAE Team Emirates riders that were pushing the pace for GC contender Pavel Sivakov. The likes of Jack Haig and George Bennett were also present but dropped in the penultimate climb.
UAE were the main driving force in the group, and after the Alto de la Colladiella only seven remained in front. Jay Vine, Pavel Sivakov, Bruno Armirail, Aleksandr Vlasov, Stefan Küng, Pablo Castrillo and Quentin Pacher.
Vine led most of the way and in the final climb Sivakov took over, aiming to climb into the Top10. Vlasov and Castrillo went with him. Movistar and EF briefly helped Quick-Step in the peloton but it was the Belgian team taking all responsibility. Mattia Cattaneo eventually led out an attack from Mikel Landa before the flat section in the Puerto de Pajares but Ben O'Connor responded and several GC rivals followed. The situation stabilized and the GC riders waited until the final 3 kilometers of the steep ascent.
Castrillo attacked at the base of the final 3 kilometers and got a gap over the other two but Vlasov managed to bridge across into the final kilometer. However in the insanely steep final ramps to the line the Spaniard managed to accelerate once again and drop the BORA rider to take his second win of the week and prove himself as the absolute breakthrough of the race.
In the peloton Roglic was also launched to attack at the base of the final kilometers but was then caught by Enric Mas who even dropped him. However in such steep gradients no-one exploded and the level was very similar among all favourites. Mas and Roglic arrived at the finish together but took only a few seconds on Ben O'Connor who defended the red jersey; with multiple riders hanging on to remain high up in GC.