Demi Vollering powered through the mountain-top fog Saturday to win the most demanding stage in the 2023 Tour de France Femmes avec Zwift and grab the leader's yellow jersey.

Vollering, seventh overnight, pulled away in the final six kilometers of the 17-kilometer final climb in the Pyrenees to take the yellow jersey from teammate Lotte Kopecky.

The Dutch rider leads the overall standings by 1 minute, 50 seconds from Kasia Niewiadoma, who was second in the stage. Defending champion Annemiek van Vleuten is third, but 2 minutes, 28 seconds back with only Sunday's 22.6-kilometer eighth-stage time trial to come.

Vollering started the short, but brutal, Pyrenean stage more than a minute behind race leader and Worx teammate Kopecky and 12 seconds behind Dutch rider Van Vleuten.

The trio were part of an elite group that pulled clear on the first of two tough climbs, the Col d'Aspin. Niewiadoma attacked first.

"I could see that Demi didn't want to work with Annemiek, so I knew they would look at each other, and I decided to take my chance on the downhill," the Polish rider said.

With less than six kilometers to go on the final foggy 17-kilometer final ascent of the Tourmalet, Vollering set off in pursuit and quickly passed the Pole.

"Demi showed how strong she is when she passed me," Niewiadoma said.

Vollering powered away.

"I went full gas to the finish," she said. "I felt good. I kept on pushing."

She battled slowly across the finish line standing on her pedals, a shadow in the mist silhouetted by the headlights of a cortege of officials vehicles.

Niewiadoma finished second, 1 minute, 58 seconds behind. Van Vleuten wobbled across the line at 2:34 in third place.

Vollering, who had plopped on the tarmac panting, rose to her feet beaming to embrace Kopecky, who had finished sixth.

"This is why we came here, to win the Tour with Demi," Kopecky said. "I think the way she did it, she showed she is the best. I wanted to enjoy my last day in yellow...but it was pretty painful."

Vollering had dropped to seventh after she was hit with a 20-second penalty Thursday for drafting behind the Worx team car that was deemed to be driving dangerously.

She had climbed a place before the start of Saturday's 90-kilometer mountain stage when Elisa Longo Borghini, who was fourth overall overnight, withdrew before the start.

The Italian veteran was suffering from a "skin infection on the upper left thigh," said her Lidl-Trek team and had to go to hospital Friday at the end of Stage 6.

"The infection is now under control, but Elisa is still in a lot of pain."