An enraged Thibaut Pinot has put the hammer down on the first major mountain test of the Tour de France, leading a French one-two ahead of overall leader Julian Alaphilippe to triumph at the top of the iconic Col du Tourmalet.

On a on Saturday of surprises, meanwhile, defending champion Geraint Thomas lost contact in the final kilometre of the brutal ascent to the cloud-clad Pyrenean pass ending 2115 metres above sea level.

Surging from the mist, Pinot jumped away from a small group 200 metres from the line to beat yellow jersey holder Alaphilippe and third-placed Steven Kruijswijk of the Netherlands by six seconds.

Thomas, whose Ineos team has been used to smash their rivals in the first high mountain stage of the Tour, crossed the line in eighth place, 36 seconds off the pace, throwing the British outfit into doubt.

His Colombian teammate Egan Bernal was fifth, eight seconds behind Pinot, who claimed his third career stage win on the Tour.

The best Australian in the stage was Richie Porte, riding for Trek-Segafredo, who finished 2:05 behind Pinot.

The in-form man of the first week, Pinot had lost one minute and 40 seconds when caught at the wrong end of a bunch split on the eve of the rest day on Monday and he had promised he would use his “rage” to bounce back.

The 29-year-old duly delivered, looking strong during the whole ascent to the Col du Tourmalet, a 19 kilometre climb at an average gradient of 7.4 per cent, and accelerated just before the final bend.

“Justice is done with that win today,” said Groupama-FDJ manager Marc Madiot.

I really wanted to win that stage, I had marked it down.

“There were delirious scenes of fans cheering us on, I had goose bumps and I needed the taste of victory,” Pinot, who has stage wins in all three grands tours and finished the Tour third overall in 2014, told reporters.

Pinot is now sixth overall, 3.12 behind Alaphilippe, who extended his lead over second-placed Thomas to 2:02 after hanging onto the favourites’ group.

“I defended the jersey like crazy today. There are some uncertainties in the race as some big leaders cracked,” said Alaphilippe, who has never previously raced for the general classification on a grand tour.

Kruijswijk is third overall, 2.14 off the pace, with Bernal 3:00 behind Alaphilippe, whose staying power was firmly under the spotlight on Saturday.

Porte has moved into 19th place overall, sitting 6:49 behind the leader.

Sunday’s 15th stage is a 185km punishing ride from Limoux, ending with a gruelling ascent up to Prat d’Albis.