Argos Shimano's Warren Barguil took this second victory in the Vuelta a España when he won the sixteenth stage.
A 146.8 kilometre stage from Graus to Aramón Formigal saw Hansen, Oroz, Boasson Hagen, Flecha, Mollema, Mondory, Wyss & Serry launch the first attack of the day out of the 150 riders still left in the race.
They had built a 42 second lead with 20kms gone but were caught at the foot of the day's first climb, the category 3 Puerto de la Foradada which King Of The Mountains leader Nicolas Edet (Cofidis) took the full points of.
Hansen, Oroz, Boasson Hagen, Flecha, Mollema, Mondor, Wyss, Serry, Huzarski, Majka, Herrada, Caruso, Martinez, Szmyd, Santaromita, Uran, Edet, Mate, Scarponi, Capecchi, Zaugg, Gastauer, Piedra and Intxausti came to the front but with 50kms gone, Astana had brought them all back together.
The day's first intermediate sprint came at Boltaña and it was , Alejandro Valverde, who collected the three-second time bonus, ahead of Andriy Grivko (Astana) and Rinaldo Nocentini (AG2R).
Back to matters on the front and the next bunch to get away were Amets Txurruka (Caja Rural), Juan Antonio Flecha (Vacansoleil-DCM), Dominik Nerz (BMC), Chris Anker Sorensen (Saxo-Tinkoff), Egoi Martinez (Euskaltel-Euskadi), Nico Sijmens (Cofidis), Bartosz Huzarski (NetApp-Endura), Rigoberto Uran (Sky) and Martin Kohler (BMC) who took over a minute's lead with eighty kilometres remaining.
Thirty kilometres later, Movistar duo Benat Ixtausti and Sylvester Szmyd joined the group of escapers on the climb up the Cotefablo.
Nico Sijmens (Cofidis) was first over that climb as the group of escapers swelled to now include Amets Txurruka (Caja Rural), Juan Antonio Flecha (Vacansoleil-DCM), Dominik Nerz (BMC), Chris Anker Sorensen (Saxo-Tinkoff), Egoi Martinez (Euskaltel-Euskadi), Nico Sijmens (Cofidis), Bartosz Huzarski (NetApp-Endura), Rigoberto Uran (Sky), Martin Kohler (BMC), Sylvester Szmyd (Movistar), Benat Inxtausti (Movistar), Christian Meier (Orica-GreenEdge), Warren Barguil (Argos-Shimano), Vladimir Gusev (Katusha), Niki Sorensen (Saxo-Tinkoff), Ben Gastauer (Ag2r-La Mondiale) and Juan Manuel Garate (Belkin).
With 22.7kms to go, their gap to the peloton was 3.24. Riders went off the front of the group including Garate of Belkin and Friday's winner Warren Barguil of Argos Shimano.
The 21 year old from Pluet - Barguil went away on his own with eight left and he quickly established a 38 second lead on the chasers.
Out of nowhere, Team Sky's Rigoberto Uran caught up to him as did Nerz and Husarski but the line came and there Barquil to win in 3.42.32 beating Uran and Huzarski.
Back down the road, race leader Vincenzo Nibali was struggling and Rodriguez, Horner, Valverde and Pinot were all able to pull time back on the Astana rider who leads Horner by 28 seconds.
Barguil told La Vuelta.com: "Firstly, I’m a bit sick. Yesterday, I wasn’t feeling well. When I got caught by the group of Alex [Geniez], I thought it was useless to insist with the only hope of finishing tenth. Today, I was told to stay calm. But I was impatient to go ahead. When I was alone in the lead in the final climb, Uran came across and attacked me straight away. It was a mental game for me to stay at his contact. For the sprint, I maneuvered him well. It came from my experience of losing a race against [former junior world champion] Olivier Le Gac in similar conditions last year. It’s been tight. Even with one stage win under my belt, my desire to win was intact. It’s super!
"It’s not my style to give up. Yesterday, it rode too much in the first climb. I’m recovering pretty well from my efforts but two days of rain have hurt. My directeur sportif told me to stay in the wheels today but I take cycling as a game. It’s an enormous pleasure to be at the front."