Mathias Frank victorious in stage 17 as favourites mark each other out

Frank, the 29-year-old all-rounder from the soon-to-be-folding IAM Cycling team, attacked from a 28-man break alongside Dario Cataldo (Astana) before dropping the Italian on the savagely steep final climb at the conclusion of the hilly 177.5km stage from Castellon.

Despite a spirited slow-speed chase from Leopold Konig (Team Sky) and Robert Gesink (LottoNL-Jumbo), Frank held on to win the first Grand Tour stage of his career by six seconds ahead of the Czech Republic’s Konig. Dutchman Gesink – winner of stage 14 atop the Col d’Aubisque – finished third a further five seconds back.

Twenty-three of the initial 28-man group had crossed the line by the time Spaniard Alberto Contador (Tinkoff) led the main favourites home three minutes and 27 seconds in arrears.

Repeatedly distanced on the taxing double-digit final gradient, Britain’s Chris Froome (Team Sky) rallied to finish just behind Contador and marginally ahead of red jersey rival Quintana and his fellow Colombian Estaban Chaves of Orica-BikeExchange.

The GC stalemate ensured that Quintana retained his commanding 3:37 lead over Froome – the triple Tour de France winner – with four days of the race remaining.

A feisty start to the sweltering stage saw numerous riders try their luck before Spaniard Omar Fraile (Dimension Data) pinged clear on the first of four categorised climbs to pick up maximum points over the Cat.2 Alto del Desierto de las Palmas and move within three points of Frenchman Kenny Elissonde (FDJ) at the top of the polka dot jersey standings.

The day’s break finally formed after 45km of racing as a strong group of 27 riders – including Movistar duo Imanol Erviti and Jose Herrada, Sky duo Konig and Michal Golas, IAM Cycling trio Frank, Clement Chevrier and Marcel Wyss, and Dutchmen Gesink and Bram Tankink from LottoNL-Jumbo – rode clear of the Movistar-led pack.

When the leaders were joined by Maxime Bouet (Etixx-QuickStep) it meant that only two teams – Giant-Alpecin and Cannondale-Drapac – were unrepresented in a break which quickly built up a maximum lead of almost seven minutes.

Italian Kristian Sbaragli took maximum points over the Alto de la Sarratella and the Alto de Benasal to protect the polka dot interests of his Dimension Data team-mate Fraile. Meanwhile, the chase back in the peloton was being carried out by the BMC team-mates of stage 16 winner Jean-Pierre Drucker on a day their American GC rider Tejay Van Garderen withdrew from the race.

Anticipating a big shake-out towards the final climb, Frank and Cataldo joined forces with 30km remaining to open up a small gap over their fellow escapees on the rolling approach to the ninth of ten summit finishes on this year’s particularly demanding 71st edition of the Vuelta.

The leading duo held a gap of 25 seconds at the start of the 3.9km climb – which was being used for the first time in Vuelta history. With an average gradient of 12.7% it posed a severe test – but one which Frank tackled with aplomb.

The Swiss dropped Cataldo inside the final two kilometres and only looked back to check that the approaching Konig and Gesink would not be able to catch him before the summit.

“My big goal before coming here was to win a stage and I’ve already come close a couple of times so I’m now super happy,” said Ag2R-La Mondial-bound Frank, who became the eleventh rider in this Vuelta to take a maiden win on a Grand Tour.

"I’ve had a rough season, not much was working as I wanted – I had to abandon the Tour de Suisse and the Tour de France. So I came here and I told myself I want to have fun, get a good feeling back. To finally have a victory after more than two years [at IAM Cycling], winning a Grand Tour stage, it’s just amazing."

Following Jonas Van Genechten's sprint win in the opening week, Frank’s victory was IAM Cycling's second in the Vuelta after scaps in both the Giro d'Italia and Tour de France – a strong return for a team that will fold at the end of the current campaign.

Back with the race favourites, it was the Orica-BikeExchange team of Chaves and Britain’s Simon Yates who set a fierce tempo going onto the climb before Movistar drowned them out as the road headed uphill.

Contador put in the first big dig to open up a small gap which Quintana and Chaves were able to close. Britons Froome and Yates, however, struggled with the steep gradient and dropped back on the maximum 22% ramp.

Froome kept his cool and rallied – rejoining his rivals in the final kilometre before closing the gap once again after being distanced by a late surge from Chaves.

Yates was unable to match his battling compatriot, the youngster conceding the best part of a minute but retaining his fifth place on GC albeit now more than six minutes down on Quintana. Froome and Chaves are still separated by 20 seconds with Contador just five seconds off the virtual podium.

The Vuelta continues on Thursday with the 200.6km stage 18 – another rolling affair with one second-category climb and numerous hills and ridges ahead of a downhill finish in Gandia.