Poland's Niewiadoma fights off Vollering to win first Tour de France Femmes title
Niewiadoma crossed the line in fourth place and broke down in tears as she realised she had done enough to keep the yellow jersey by a margin of just four seconds, with Pauliena Rooijakkers taking second place on the stage and Evita Muzic third.
"I went through such a terrible time on this climb, so to arrive at the finish line to learn that I've won the Tour de France is insane, it's mind-blowing," Niewiadoma said.
Niewiadoma, who finished third in the previous two editions of the Tour, still had energy left after the finish, raising aloft her bike in celebration, while an exhausted Vollering lay on the ground crying in disappointment.
Vollering (SD-Worx-Protime) began the day eighth overall, one minute and 15 seconds down on Niewiadoma (Canyon–SRAM), but the Dutch rider was expected to be the main danger on the 149.9-km ride from Le Grand-Bornand to Alpe d'Huez.
She won the stage first but then had an agonising wait as an exhausted Niewiadoma dragged herself to the line one minute and one second behind Vollering.
Vollering took an extra 10 seconds for the stage win, but missed out by the narrowest of margins on what would have been an exceptional comeback after losing the yellow jersey following a crash on stage five.
Her expected move came close to the summit of Col du Glandon, with more than 50km left to ride, and Niewiadoma was unable to keep pace. In the end Pauliena Rooijakkers was the only one able to go with Vollering.
Rooijakkers was two seconds ahead of Vollering in the general classification and had little intention of helping her fellow Dutchwoman, who had to do most of the work but couldn't shake off her pursuer until the finish line.
Behind them, Niewiadoma fought hard to lose as little time as possible. She had two others for company, Muzic and Gaia Realini, but as they climbed the Alpe d'Huez the gap began to increase going out to over a minute.
Rooijakkers, who finished third overall, attacked in the closing kilometres but Vollering stuck with her and won the fight between the Dutch duo for the stage. Niewiadoma, meanwhile, did just enough to win the real battle on one of cycling's most famous climbs.
"It's so crazy to be honest because the whole stage was such a crazy rollercoaster," Niewiadoma said.
"I had a really bad moment on Glandon and then on the descent I was able to kind of rebuild myself and refresh."