The question now is whether Sky will pay for the effort on Sunday and run out of juice on the 181.5-kilometer (112-mile) Stage 9 from Nantua to Chambery in the Alps, arguably the most grueling of this Tour's 21 stages.
Froome, the defending champion who came into the eighth stage as the overall classification leader, was able to retain his yellow jersey despite a mistake 45km from the finish.
"It was good to see them pull on the front", said Australian Richie Porte of the rival BMC team, who is 39 seconds behind Froome overall, in fifth place.
Lilian Calmejane of Direct Energie has won Stage 8 of the Tour de France at Station des Rousses as the race entred the Jura mountains, the second of the country's five mountain ranges it will tackle this year.
An ecstatic Calmejane shook his head and raised his arms as the 24-year-old climber crossed the finishing line in the ski resort to become the second Frenchman to win a stage in the 2017 Tour, following Arnaud Demare's success on stage four. "I hope there's some exhausted legs among them tomorrow". Thomas dusted himself off and quickly rejoined the race, too, and Froome said his teammate was uninjured.
"The boys went into the corner a bit hot and I was just looking to my side for a split-second so I was late braking", the Welshman said.
"One minute everything is going well, the next you're in the ditch with your team-mate over the barrier lying next to you".
Calmejane had a 30-second lead by then and he increased it on the plateau to the finish despite easing up at one point to stretch his legs due to cramp, to win by 37sec. "It would have been so sad to lose the stage like that".
Robert Gesink of the Netherlands finished second while Guillaume Martin of France was awarded third, leading led a group of riders who were credited with finishing 50 seconds back, including Nathan Brown of the United States in ninth place.
It was very much Calmejane's day, though, attacking with 6km to go on the last category one climb and taking the polka dot jersey in style with a magnificent solo ride.
"It's huge", said Calmejane, whose previous best result at a Grand Tour came when he won a stage of last year's Vuelta a España.
An initial breakaway group of Maxime Bouet, Manuele Mori, Yohann Gène and Dylan van Baarle opened up a three-minute gap just outside Troyes but, with temperatures reaching 31 degrees Celsius and the wind also playing a part, staying ahead of the peloton was always going to be a tough ask and they were reigned in with 7km to go.
"It was everything I was dreaming of".