Any notion Geraint Thomas (Team Ineos) is not a serious threat to successfully defend his Tour de France title at this year's edition seemed to fade as the 33-year-old Welshman surged on the steep slopes of La Planche des Belles Filles during Stage 6 on Thursday.
A well-timed kick helped Thomas gain valuable time on his general classification rivals, including four seconds on Ineos team-mate and co-leader Egan Bernal in what would be a nine-second swing from the previous day.
“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 afterward.
“When Movistar went and [Alejandro] Valverde was 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 hard all day before that. But it was a good day in the end."
The final, one of seven categorised climbs on the day for the race's first real mountain stage, featured a brutal 24 per cent gradient toward the finish.
Although the stage was won by Dylan Teuns (Bahrain-Merida) and the yellow jersey passed from Stage 3 winner Julian Alaphilippe (Deceuninck-Quickstep) to Stage 6 runner-up Giulio Ciccone (Trek-Segafredo) thanks to a six-second bonus for second place.
Thomas was able to place himself at the pointy end of the GC contenders with a fourth-place finish two seconds ahead of Frenchmen Thibaut Pinot (Groupama-FDJ) and Alaphilippe, and seven seconds over Colombian Nairo Quintana (Movistar).
Christophe Mallet and David McKenzie analyse the entrails of a pulsating Stage 6 which finished on La Planche des Belles Filles, giving the race its first real look at the shape of the overall contenders.
“It’s one of those climbs where you really have to be patient and when [Julian] Alaphilippe went pretty early, at like 800m to go, I just had to have the confidence to let him go and ride my own tempo and try and ride it all the way to the line. I was starting to blow though as it was solid, overall it was a decent day.”
Fellow GC threats Jakob Fuglsang (Astana), Mikel Landa (Movistar) and Richie Porte (Trek-Segafredo) join Bernal in losing nine seconds, while Adam Yates (Mitchelton-Scott) and Dan Martin (UAE-Team Emirates) lost 14 and Thomas's former Sky team-mate Rigoberto Urán 18.