Geraint Thomas’s Tour de France title defence was hanging by a thread after the toughest mountain stage yet of the 2019 race saw him lose more time to the overall race leader Julian Alaphilippe.

Thomas was unable to follow the decisive accelerations in the final moments of a breathless stage that included well over 3,000 metres of climbing, as the peloton raced to the summit of the Col du Tourmalet. The 117.5km stage was abridged by several kilometres to allow police to clear the road of environmental protesters near Ossun.

As Alaphilippe, Thibaut Pinot, Steven Krusijwijk and his Ineos teammate Egan Bernal closed on the summit finish, Thomas faltered and was forced to concede yet more ground to the unstoppable Frenchman. Over half a minute ahead of him, Pinot took the most memorable stage victory of his career by six seconds from race leader Alaphilippe. A disconsolate Thomas described the stage as “Not the best day”.

“I just didn’t feel quite on it from the start,” the Welshman said. “I was quite weak. At the end I knew I just had to pace it. I didn’t really attempt to follow when they kicked.

“I just thought I should ride my own pace rather than follow them and blow up on the steepest bit at the end. It’s disappointing. I just tried to limit the damage.”

Ahead of him his Colombian teammate Bernal was showing fresher legs, shadowing Alaphilippe through the final metres to move up the classification to fourth overall. With Thomas apparently on the slide, the 22-year-old may yet prove to be Team Ineos’s best hope of a top-three finish.

But Thomas’s sports director, Nicolas Portal, shrugged off the setback. “Sometimes you can have a bad day,” Portal said. “Egan was there so that’s good, but I was a little bit surprised that Geraint struggled, of course. Clearly Alaphilippe is the man of this Tour, so chapeau to him.”

With seven stages left, Thomas on the ropes and Alaphilippe showing no sign of weakening, Portal conceded that the Ineos team may now have to revise its strategy.

“Probably we are going to have think a little bit differently. First, though, we are going to talk to the guys and debrief. It’s quite a big gap to Alaphilippe for sure.”

But Portal refused to confirm that his team would go on the offensive. “We will see, first we need to think,” he said. “If you want to attack you have to have the legs and at the moment, nobody can attack.”

Bernal, riding in support of Thomas so far in this year’s Tour, confirmed that he had been told to ride his own race. “I was available to help him but through the radio, they told me to not wait for him,” he said of his instructions. “I don’t know if we can win the Tour de France. I know that the defending champion is my teammate and I won’t go against the instructions of my team. If I’m asked to help, I will do. If I’m given freedom, I’ll try to make the best of it.”

Ten kilometres from the top of the Tourmalet, as the final rider from the earlier breakaway was reeled in by a dwindling peloton, the first cracks began to show as Nairo Quintana failed to keep pace with his Movistar teammates.

One by one big names wilted on the 19km climb, as Richie Porte, Enric Mas and Thomas’s key teammate, Wout Poels, fell back until, four km from the summit, Thomas himself appeared to be struggling. By the time Pinot took the stage win, the 2018 champion had lost another 30 seconds to Alaphilippe.

Meanwhile, the mutterings of scepticism over Alaphilippe’s performances are growing, although he has yet to face the outright derision that has dogged Britain’s Chris Froome in the past.

“I knew that a yellow jersey changed you,” Alexandre Vinokourov, manager of the Astana team said after the Frenchman’s win in Friday’s individual time trial. “But I didn’t know it could make you fly.”

Vinokourov, banned for blood doping during his own career, reiterated the point on Saturday morning. “If he arrives in Paris in yellow it will be a big surprise,” the Kazakh said, before adding cryptically, “I don’t understand cycling.”

Such is the lot of the yellow jersey wearer in the modern Tour. Cynicism and scrutiny follows their every pedal stroke. Thomas, meanwhile, continues to put a brave face on his hopes of a second Tour win, even as it slips away. Asked after the finish if he could still take a second yellow jersey, he responded: “Yes, why not?”

Tour de France 2019: stage 14 takes race up to finish on Tourmalet – live! Read more