Kasia Niewiadoma won the 2024 women’s Tour de France by four seconds, the narrowest margin in the history of either the women’s or men’s race, clinging on to the yellow jersey, despite an Alpine assault from the defending champion, Demi Vollering.

On Saturday afternoon, a defiant Niewiadoma had said: “I lost four seconds, so that’s nothing,” after Vollering had picked up that much via time bonus. Twenty-four hours later, though, for the Pole and her Canyon-SRAM team, four precious seconds at the top of Alpe d’Huez meant everything.

“Four seconds seem to be magical now,” she said. “Throughout my whole career there were so many times I missed out on victories. I feel like this week was perfect for me and my team. To be able to win big races, you need everything on your side.”

Related: Niewiadoma wins Tour de France Femmes by four seconds in thrilling final climb – live

The 29-year-old had earlier described the final stage of the Femmes as “the most important day of my career and maybe, my team’s existence”. Her tearful disbelief, at sealing overall victory by such a slim margin, bore that out.

In a nail-biting drama that came to a head on the 21 hairpins of the steep climb, Niewiadoma fought off all her main rivals, during a stage in which, at one point, all had seemed lost for her.

As the leaders began the climb to the ski station, five riders were in play for final victory. Niewiadoma, lacking any teammates, was under intense pressure with the top three on the general classification separated by just 10 seconds, as they closed on the finish.

Vollering’s initial make-or-break attack had come on the Col du Glandon, the penultimate climb, 55km from the finish. The SD Worx Protime rider made her move 3km from the summit, with Niewiadoma unable to respond.

As mountain mist swirled around the peloton, so it seemed to close in on the Pole’s hopes of overall victory. Niewiadoma chased hard over the top of the Glandon, while Vollering rode clear and made up her overnight deficit of 1min 15sec to the race lead on the long descent to the valley road at Allemond. But in the ­ensuing kilometres, tactical ­complications and conflicting objectives worked against Vollering. As she has, for much of the race, the 2023 champion did most of the hard work on her own.

Aside from a virtuoso turn by Niamh Fisher-Black in the final kilometres of the Glandon, she had to make the difference herself, even on the flat road leading to the Alpe, when her Dutch compatriot Pauliena ­Rooijakkers, also a contender for final victory, refused to collaborate.

Vollering got so frustrated that, after remonstrating with ­Rooijakkers, she pushed the Fenix-Deceuninck rider on the shoulder. Her anger had little effect, however, and by the bottom of the Alpe, her lead on Niewiadoma had dwindled to only 44sec.

Related: Sunflowers and windmills: 2024 Tour de France Femmes – in pictures

On the 21 hairpins, a classic pursuit took shape: Vollering and Rooijakkers were chased by Niewiadoma, the Italian climber Gaia Realini of Lidl-Trek and France’s Évita Muzic, riding for FDJ‑Suez. All five harboured hopes of a top-three finish.

Vollering’s relentless pace clawed back more time and, with 10km still to race, overall victory was in view. But the tables turned once more when the defending champion began to ­falter, with 3km remaining. It was just enough to end her hopes.

Vollering could point to a series of mishaps: her sometimes erratic team support, the dramatic crash at Amnéville in which she lost her race lead, and the lack of support ­during her attack to the Alpe. “I’m a bit disappointed that I couldn’t win the yellow jersey, just by four seconds,” she said. “That’s a bit sour for me at the moment.”

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In the end, the destiny of the ­closest Tour in its history was played out in the final few metres of a race that was 950km long. Vollering ­rallied to take a prestigious stage win, but the resilient Niewiadoma chased once more, crossing the line in tears, as she realised she had held on to win.

“Hopefully this will attract more ladies to hop on the bike,” a beaming Niewiadoma said. “It feels amazing to be at the top step, to be rewarded for all the hard work. We’re very proud to be at the top.”