Poland's Katarzyna Niewiadoma won her first women's Tour de France title by just four seconds on Sunday as she dug in during the race's grueling final Alpine ascent.

The 29-year-old Canyon SRAM rider summited the daunting Alpe d'Huez mountain one minute one second behind stage winner Demi Vollering to maintain her grip on the yellow jersey.

"It's so crazy to be honest, the whole stage was such a crazy rollercoaster," said a visibly emotional Niewiadoma.

"I've gone through such a terrible time on this climb, like I hated everything, then to arriving at the finish line and learning that I won Tour de France, which is insane! It's so mind-blowing."

The Tour was turned upside down on Thursday during the fifth stage when Vollering was caught up in a huge crash six kilometres from the finish in Amneville, losing 1min 47sec on the leader.

But the Dutchwomen fought her way back and going into the final stage, she had cut that gap down to one minute 15 seconds.

Reigning Tour champion Vollering then produced a barnstorming performance in Sunday's 150km slog from Le Grand-Bornand to Alpe d'Huez, outsprinting compatriot Pauliena Rooijakkers to the line to claim the stage win.

Niewiadoma struggled on the Glandon ascent and seemed set to throw away her lead as her rival surged ahead and provisionally took the lead in the general ranking at several stages.

But the Polish rider managed to regroup and fought back in the final 5km to claw back precious seconds.

Both Vollering and Niewiadoma faced a nerve-wracking wait once across the line for the official confirmation of who was to be the last to hold the yellow jersey in the third edition of the women's Tour.

The duo dissolved into tears of drastically varying emotions when the news filtered through that the Pole had claimed a historic win by the narrowest of margins.

After third-placed finishes in the previous two Tours and a disappointing eighth-place finish at the 2024 Olympic Games road race, the victory tasted even sweeter for Niewiadoma.

"I think last year's third place was there to reward me with this victory and same as two weeks ago I was so disappointed getting stuck behind a crash during the Olympics," said the Limanowa-native.

"I feel like during this week, all the stars aligned for my team and for myself."

Niewiadoma completed the eight-stage tour in 24 hours 36min 07sec, a mere four seconds in front of second-placed Vollering with Rooijakkers completing the podium just a further six seconds behind.

"This is one of the greatest achievements in Polish sport. Bad luck at the Olympics, now a bit of luck, but above all skill," wrote Polish Prime Minister Donald Tusk on X.