Vollering grasps women's Tour lead with victory atop Tourmalet
Vollering, seventh overnight, pulled away in the final 6km of the 17km final climb in the Pyrenees to take the yellow jersey from team-mate Lotte Kopecky.
The Dutch rider leads the overall standings by one minute and 50 seconds from Kasia Niewiadoma, who was second in the stage. Defending champion Annemiek van Vleuten is third, but two minutes and 28 seconds back with only Sunday's 22.6km eighth-stage time trial to come.
Vollering started the short but brutal Pyrenean stage more than a minute behind race leader and Worx team-mate 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 that they would look at each other and I decided to take my chance on the downhill," the Polish rider said.
Vollering said she had been happy to let Niewiadoma go.
"Annemiek said to me, 'If we don't both ride, we'll both lose'. I said, 'That's fine with me'. It wasn't up to me to ride. I still had teammates with me."
'Full gas'
With less than 6km to go on the final foggy 17km final ascent of the Tourmalet, Vollering set off in pursuit, quickly passing the Pole.
"Demi showed how strong she is when she passed me," said Niewiadoma.
Vollering powered away.
"I went full gas to the finish. I felt good," she said. "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 one minute and 58 seconds behind. Van Vleuten wobbled across the line at 2:34 in third place.
"I came up against an opponent who was better than me and I didn't have a great day. But even if I'd had an exceptional day, I wouldn't have beaten Demi. She was on another level," said Van Vleuten.
Vollering who had plopped on the tarmac panting, rose to her feet beaming to embrace teammate Kopecky, who had finished sixth.
"This is why we came here, to win the Tour with Demi," said Kopecky. "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."
