Chris Froome has taken a huge step towards succeeding Sir Bradley Wiggins as Tour de France champion on the first mountain stage of this year's race at Ax 3 Domaines, winning at a canter with team mate Richie Porte second after Team Sky blew the opposition apart in the Pyrenees.

It's the second year running that Froome has won on a stage on the second Saturday of the Tour – last year, he won at La Planche des Belles Filles, on a day when Wiggins rode into the yellow jersey he would keep all the way to Paris. Tonight, it's Froome who is in the maillot jaune.

Porte finished a little shy of a minute down on his team leader at the end of the 195km stage from Castres, with Alejandro Valverde a further 15 seconds back in third place. Some potential pre race rivals lost huge time to Froome, with Alberto Contador coming home the best part of two minutes down.

Movistar’s Nairo Quintana, identified by Chris Froome as one of his biggest potential rivals for the yellow jersey, hit that final climb with an advantage of just 30 seconds over a GC group of no more than 25 riders, with Europcar’s Pierre Rolland in between the Colombian and the pursuing riders.

The chase was being led by Team Sky, but by this point Froome had just two men to help him, Peter Kennaugh and Richie Porte, as they headed through the spa town of Ax-les-Thermes to begin that final ascent, covering 7.8 kilometres with the gradient averaging 8.2 per cent.

The pace Quintana was setting up front on his own, and that being set at the front of the chasing group by Kennuagh, winner of team pursuit gold at the London Olympics last year, put a number of big names in trouble.

When Porte took over from his younger team mate on the final climb, a number of Sky's big rivals were already suffering and got distanced, among them former Tour de France champions Andy Schleck of RadioShack-Leopard and BMC Racing’s Cadel Evans, who would lose 4 minutes.

The latter’s team mate Tejay van Garderen, winner of the white jersey as best young rider last year, was also dropped and lost nearly a quarter of an hour. Also left behind was the man who headed the young rider classification this morning, Michal Kwiatowski of Omega Pharma-Quick Step.

Others pinging off the back included the Garmin-Sharp pairing of Dan Martin and Andrew Talansky, as well as another man seen as a potential challenger for the overall, Katusha’s Joaquim Rodriguez.

With 5 kilometres of the climb left, just five riders were left from that group as they caught Quintana – Froome, Porte, Valverde, Contador and his Saxo-Tinkoff team mate, Roman Kreuziger.

Immediately, Froome went on what would be a decisive attack to win the stage and take the maillot jaune.

It’s early days, and there are plenty of mountain stages still to come – Contador is said to be aiming to peak in the final week in the Alps – but even this early, the race looks like Sky’s to lose.

The stage had begun with four riders getting clear of the peloton to form a break that would have an advantage of around 9 minutes at one point but one by one would fall back on the huge climb of the Port de Pailhères, 15.3 kilometres of climbing at an average gradient of 8 per cent.

Besides new Dutch national champion Johnny Hoogerland of Vacansoleil-DCM, the quartet comprised Christophe Riblon of AG2R La Mondiale – looking to repeat his victory in Ax 3 Domaines three years ago – plus Sojasun’s Jean-Marc Marino and the Cofidis rider, Rudy Molard.

That climb of the Port de Pailhères officially began 45 kilometres from the finish, but the road had begun to rise even before the intermediate sprint at Quillan, 37 kilometres earlier.

There, André Greipel of Lotto-Belisol pipped yesterday’s stage winner Peter Sagan of Cannondale to take fifth place, but the Slovak still has a commanding lead of 93 points in the standings for the green jersey.

Meanwhile, despite the certainty that Daryl Impey would not be in the yellow jersey this evening, his Orica GreenEdge team spent much of the day controlling the pace at the front of the main group ahead of those two big climbs towards the end of the stage.

On the Port de Pailhères itself, first Belkin’s Robert Gesink, then Europcar’s Thomas Voeckler launched attacks, as would Euskaltel’s Mikel Nieve, but it was Quintana who made the one that stuck.

The 23-year-old, who now takes the white jersey, caught and passed Riblon the last man standing from the break and took the Souvenir Henri Desgrange prize for being the first rider over the highest point of this year’s race.

Behind, Rolland had made his move. The double points on offer at the summit finish mean it’s Froome who now leads the mountains classification, but Rolland did enough to ensure he’s second, meaning he’ll have another chance tomorrow to get out his polka dot ensemble – including shorts and bike to match the jersey – by virtue of Froome wearing the maillot jaune.

That stage tomorrow, the second and final day in the Pyrenees, covers 168.5km from Saint-Girons to Bagnères de Bigorre and features five big climbs – significantly, however, there’s no summit finish.

It provides the first opportunity for the teams whose GC ambitions were thrown into chaos by Sky to today to start providing a response, and it’s certain there will be a lot of reflection on this afternoon’s events in the hotels of the likes of BMC Racing, Movistar and Saxo-Tinkoff this evening.