Geraint Thomas’s hopes of taking the yellow jersey at the foot of the Pyrenees wilted in the heat of the afternoon after his path to a second Tour victory became much more complicated following another extraordinary performance from the overall race leader, Julian Alaphilippe.

On the centenary of the introduction of the yellow jersey Alaphilippe’s stage win in the only individual time trial in this year’s race left his rivals slack-jawed with astonishment as he surpassed any prior time-trial showings with an emphatic win that increased his overall lead on the defending champion.

Tour de France 2019: Alaphilippe storms to stage 13 time trial win – as it happened Read more

“If he can keep that up, he’ll win,” a stunned Thomas said as he warmed down after the stage. “I didn’t really expect that. He’s obviously going incredibly well, so he’s certainly the favourite and the one to watch at the minute.”

Last to start the 27.2km individual time trial as wearer of the yellow jersey, the Frenchman countered all expectations, beating Thomas by 15 seconds to increase his lead on the Welshman, who is now the only rider within two minutes of Alaphilippe.

“It wasn’t too bad,” Thomas said of his own performance. “It just felt like I was just overheating a bit so I was trying to deal with that. It’s not an excuse; it’s the same for everyone. It was OK – just in that last bit I didn’t really feel it.”

What had been portrayed, after the crosswinds carnage in Albi, as something of an Ineos shoo-in for both Thomas and Egan Bernal, now looks increasingly challenging for a team that have become accustomed to success in the Tour. “I didn’t expect that I could win, it’s unbelievable,” Alaphilippe said. “I don’t think I’m a threat [overall], though, but tomorrow is the first summit finish. It’s completely different to what we have done until now. I want to be in the front as long as possible, even if it’s only for tomorrow. I don’t want to know beyond that.”

The time trial shuffled the pack as riders that had slipped out of the picture, such as Rigoberto Urán, moved up the rankings to within touching distance of the top-three placings. Others, including Adam Yates, slipped back. But there is no doubt that France may now start dreaming again after Alaphilippe stunned Thomas and Bernal with another show of panache that had the home nation swooning. Better still, for those French fans awaiting a successor to Bernard Hinault, the last French Tour champion in 1985, Thibaut Pinot made good on his promise to avenge his humiliation on the stage to Albi.

Yet Alaphilippe’s performances have been so unprecedented that in a sport still struggling with credibility issues, they have also raised eyebrows. Career-changing performances in the Tour, such as Alaphilippe’s, are now met with a degree of cynicism that was not the case in Hinault’s more innocent era.

Facebook Twitter Pinterest Geraint Thomas finished second but lost time to Alaphilippe in the overall standings. Photograph: Anne-Christine Poujoulat/AFP/Getty Images

“I am not thinking about that at all,” Alaphilippe said. “I never imagined that I would win a time trial with the yellow jersey and start the mountains with the yellow jersey. I am not here to answer to suspicions. I know the work I have done to be here,” he said. “I am the most surprised at where I am now. If it creates suspicion, I know being first always makes people talk. If I was last on general classification, I wouldn’t have this kind of question. I ride my bike the way I like, everything else makes me laugh.”

With Bernal now slipping to fifth place, almost three minutes behind Alaphilippe, and the Frenchman’s teammate Enric Mas of Spain rising to fourth place, his Deceuninck-Quickstep team appear ready to do battle with Ineos as the Tour heads into a grand finale of mountain stages.

Meanwhile the mystery over Rohan Dennis’s Tour walkout continued. The Australian world time-trial champion, who would have been a favourite to win in Pau, quit the race midway through the stage from Toulouse to Bagnères-de-Bigorre on Thursday, after a disagreement with his team erupted into a mid-race row. Even a short statement quoting Dennis but issued by his team failed to shed much light. “I am very disappointed to leave the race at this point,” it said. “The individual time trial had been a big goal for me and the team, but given my current feeling it was the right decision to withdraw earlier today. I will hopefully be back competing in this great race again over the coming seasons.”

Further clues to his mind-set emerged in an interview with the Stanley Street Social podcast, recorded last winter. “There are times when I think: ‘What the hell am I doing?’” Dennis said. “In 2018 I reckon there were half a dozen times when I thought: ‘I could quit – right now.’ But after a while you snap out of it and then you realise why you like it again.”

Dominant Marianne Vos wins La Course 2019 after powerful finish in Pau Read more

On the day that Marianne Vos took her second victory in La Course, the bolted-on one day women’s race organised by the Tour’s parent company ASO, there were more concrete suggestions that a women’s Tour de France may soon be forthcoming.

Speaking to Reuters, a senior Tour official revealed that a stand-alone women’s Tour was in the planning stages. “We cannot have a women’s Tour de France at the same moment as the men’s Tour,” he said, “because it would be logistically impossible. The Tour has grown so much and is so big that having two races at the same time would not be feasible.”

He added that any women’s race created by ASO “would be to women’s cycling what the Tour de France is to men’s cycling.”

Meanwhile the men’s race now turns its attention to the monumental summit finish to stage 14, at the Col du Tourmalet, a 19km climb, at an average of 7.4%. As the first of the 2019 Tour’s mythic climbs, the Tourmalet, a day after a sweltering and gruelling time trial, may reveal even more about the outcome of a surprising race that is now entering its crucial final week.