LA PLANCHE DES BELLES FILLES, France- - Defending champion Geraint Thomas gained time on his rivals in a brutal finish in the sixth stage of the Tour de France as several top guns cracked in the lung-busting ascent to La Planche des Belles Filles on Thursday.
Belgian Dylan Teuns prevailed after a long breakaway at the end of the 160.5-km ride from Mulhouse ahead of Italian Giulio Ciccone, who claimed the overall leader's yellow jersey to follow his first place in the mountains classification at the Giro d'Italia.
But all eyes were on the overall contenders in the 7km final climb at an average gradient of 8.7% that featured a final gravelled section where standing up on the pedals -- a usual position for the pure climbers -- was almost impossible.
Thomas took full advantage of the terrain to produce brutal acceleration and take fourth place, 1:44 behind Teuns, who snatched his maiden stage win on a grand tour.
"I felt pretty good. I thought it would be a more solid day - it’s never easy, but it was steady for the first three climbs," said Thomas, whose performance lifted some of the doubts about his condition after a crash forced him out of the Tour de Suisse last month.
"When Movistar went and (Alejandro) Valverde were riding it was solid, I was feeling pretty good - I was just unsure as on those steep climbs I was expecting Richie Porte, Nairo Quintana and obviously Egan to jump up there, so I was hoping for it to be hardest all day before that. But it was a good day in the end," he added.
France's Thibaut Pinot, who had been tagged as the pre-stage favourite on an ascent situated 15km from his home town, reacted swiftly in the last 200 metres on asphalt to limit the damage to a two-second loss.
Thomas's Ineos team mate Egan Bernal of Colombia appeared less fresh and lost nine seconds to the Briton, prolonging the status quo in the team's shared leadership.
Bernal, 22, was named as co-leader by principal Dave Brailsford and it looked like he would overthrow Thomas after gaining five seconds on him in Monday's third stage.
Overall, Ciccone leads France's Julian Alaphilippe, who wore the yellow jersey in the morning, by six seconds after the Deceuninck-Quick Step rider had to settle for sixth place.
"It's an incredible day, I just can't realise. It's the dream of any person who loves cycling," said the 27-year-old Ciccone, who snatched the jersey thanks to 14 bonus seconds he grabbed at top of the Col de Chevreres and by finishing second in the stage.
Among the top contenders, Thomas is fifth, 49 seconds behind, and leads sixth-placed Bernal by four seconds and seventh-placed Pinot by nine.
Italian Vincenzo Nibali, who was waiting for that stage to assess his form after finishing second overall in a demanding Giro d'Italia in May, lost 51 seconds to Thomas, whom he now trails by 1:07 overall.
The day also signalled the end of Romain Bardet's hopes after the Frenchman, twice a podium finisher on the Tour, lost over a minute and now lags more than two minutes behind Thomas.
"I was not at the required level today, and as hard as it is I have to face it," Bardet told reporters.
"I will try to understand what happened."
Friday's seventh stage is a 230km flat ride from Belfort to Chalons sur Saone.