The Frenchman, who had surpassed all expectations over the past three weeks, hanging on to the lead the race until two days from Paris, climbed into a team car near Val d'Isere as the stage was aborted with 20km to go due to ice, deep rain water, and even mudslides. The rest of the parcours, including the final climb to Tignes, would not be ridden, and the finish line was retrospectively placed at the top of the Col de l'Iseran, which had been crested 10 minutes or so before.
Alaphilippe, who'd betrayed cracks of weakness at Prat d'Albis last Sunday and on the Col du Galibier on Thursday, had finally started to find himself in real trouble on the mighty 2770-metre Col de I'Iseran.
Egan Bernal, who'd started the day second overall at 1:30, had attacked some five kilometres from the summit, and established a lead of more than two minutes over Alaphilippe, who was himself more than a minute down on Geraint Thomas, Steven Kruijswijk, and Emmanuel Buchmann.
With times taken at the top of the Col I'Iseran, the yellow jersey passed to Bernal, who now leads the Frenchman by 45 seconds, with his teammate Geraint Thomas third at 1:03.
"I gave everything. I can't have any regrets. I gave everything and I was beaten by someone stronger. That's it," Alaphilippe said, giving his initial reaction to French television.
Having taken the famous maillot jaune - on its 100th anniversary - at Epernay on stage 3, lost it on La Planche des Belles Filles, regained it in Saint Etienne, and defended it in the time trial, through the Pyrenees, and into the Alps, it has been quite a ride for Alaphilippe.
It is, however, over. Despite still lying second, he has already come to terms with the idea he won't be winning the 2019 Tour de France.
"I don't think so. It was already a dream to wear the jersey. I've pursued the dream for a long time – a lot longer than I ever imagined. Voila, that's how it is.
"From the moment I took the jersey, my plans didn't change. I didn't allow myself to dream, from one day to the next, about winning the Tour de France. But it's true, I have fought every day to keep the jersey up to now, up to the very top of the Iseran, on the descent, and now to get into the team car to go to the hotel.
"I want to thank everyone who supported me in this Tour. I've been carried along by the madness of the yellow jersey. A big, big thanks, from the bottom of my heart. As I'd said, whatever the result, I wouldn't have any regrets, and today I don't have any regrets. I have everything."