France's Julian Alaphilippe after losing the overall lead on Thursday / © AFP
Defending Tour de France champion Geraint Thomas defied his doubters Thursday as Belgian Dylan Teuns won stage six and his breakaway partner Giulio Ciccone snatched the yellow jersey by just a few seconds on an iconic mountain stage.
Teuns won the ultra-tough mountain stage to Planche des Belles Filles when he and Ciccone crossed the summit finish line as the sole survivors of a mass breakaway.
"It was so steep, but I love these kind of finishes, I'm pretty good at this kind of finish," said Teuns, a Belgian who rides for Bahrain Merida.
Ciccone was less calm about his feat.
"It's just unbelievable," said the Italian after taking the overall lead from Frenchman Julian Alaphilippe by just six seconds.
Alaphilippe put in a heroic defence of his lead, but missed out due to the bonus seconds over the final two summits saw the young Italian edge ahead of him.
"It feels strange, to have the yellow jersey on my back feels so strange." said Ciccone.
"I wanted to win the stage for the team but I never believed it would be possible to take the lead," said the 24-year-old who rides for the same Trek-Segafredo team as Richie Porte.
Just behind this victorious pair the struggle between the contenders to win the Tour de France itself played out when defending champion Geraint Thomas suggested that the doubters who had called him a one-hit wonder after his 2018 win with Sky might be wrong.
Thomas and his co-captain Colombian 22-year-old Egan Bernal, who dropped nine seconds to the Welshman, were part of an Ineos team effort that controlled the pace over the most of the course as the peloton crossed seven mountains.
Other good performances on the day came from Briton Adam Yates, Irishman Dan Martin and Frenchman Thibaut Pinot, who grew up in the region.
Three of the overall contenders lost significant time as 2014 champion Vincenzo Nibali, Jumbo Visma captain Steven Kruijswijk and, to a greater extent, Frenchman Romain Bardet suffered on the slopes.