The last ascent of the 170-kilometer trek to the ski resort of Méribel was the highlight of this year’s race at 2,304 meters, winding a never-before-ridden Loze pass and with tortuous slopes of 24%.
Lopez timed his attack perfectly with just under 3 kilometers to go as Roglic accelerated away from Pogacar, who made up part of the gap but perhaps said goodbye to his chances of winning the Tour.
Roglic is 57 seconds ahead of Pogacar with four stages to go. Lopez passed Rigoberto Urán to move up to third place overall and is 1 minute, 26 seconds behind Roglic before another grueling mountain stage on Thursday. Urán dropped to sixth place.
As the riders tackled the steepest section of the Loze, where the tarmac had been laid last year on a mountain trail that is only open to bicycles, Pogacar picked up the pace with around 4 kilometers to the left while Roglič hid behind him and Uran was let loose.
Lopez then attacked and went after Richard Carapaz, one of five runners who had formed an early breakaway group and the last to be caught 3 kilometers from the end.
With Lopez ahead, Roglič attacked fellow Slovenian Pogacar, who responded well towards the end to limit the damage.
French President Emmanuel Macron was on hand to applaud Lopez as he crossed the finish line after 4 hours, 49 minutes and 8 seconds of a grueling trek that featured two of the most difficult climbs known as Hors Categorie , or out of category.
Previously, Macron had been an avid spectator in race director Christian Prudhomme’s red car, and as the camera pointed at them they were seen applying hand sanitizer. Prudhomme recently returned to racing after a period of isolation after testing positive for the coronavirus.
The other members of the early breakaway group were Julian Alaphilippe, Dan Martin, Gorka Izagirre and Lennard Kämna, winner of Tuesday’s stage with a solo effort.
They picked up the pace as they passed the magnificent Chateau de Miolans, a fortress perched on a hill that the Counts of Savoy turned into a prison from which the French nobleman the Marquis de Sade escaped at the end of the 18th century.
By the time they reached the foot of Col de la Madeleine – the first of two HC climbs of the day – they were about six minutes away from the yellow jersey group. La Madeleine is one of the most famous on the Tour and the second highest peak in this year’s race at 2,000 meters.
By the time they reached the summit after climbing 17.1 kilometers (10.6 miles), their lead over the yellow jersey group had been reduced to 1:15.
Sam Bennett kept the best sprinter’s green jersey but Benoit Cosnefroy passed out at the start of the last climb and lost his polka dot top climber jersey to Pogacar.
Defending champion Egan Bernal retired before Wednesday’s stage. The Colombian had been struggling since Friday’s stage in the Jura, where he lost more than seven minutes to the main contenders.
Stage 18 from Méribel is 175 kilometers long and another demanding with an early category 1 climb, followed by another ascent to the Col des Aravis and the Hors Category Plateau des Glières before a hilly descent to La Roche- sur-Foron.