Simon Yates soloed to his second Tour de France victory of the week on stage 15 to the Prat d'Albis as Julian Alaphilippe finally cracked and the fight for yellow came alive behind.
Mitchelton-Scott's Yates attacked with 8.7km left of the steep climb above Foix to follow up his victory on Thursday's stage 12 to Bagneres-de-Bigorre.
Behind, Groupama-FDJ's Thibaut Pinot attacked the reduced group of favourites and distanced Geraint Thomas, though the Welshman put in a late dig of his own to ensure he remained above the Frenchman in the general classification.
Alaphilippe retained the yellow jersey but the Deceuninck-Quick Step rider finally showed the signs of weakness which have been expected from a rider never considered a contender before the Tour began - but who will enjoy an 11th day in yellow on Tuesday.
His advantage over Thomas was cut by 27 seconds to one minute and 35 seconds.
Jumbo-Visma's Steven Kruijswijk stuck with Thomas to remain 12 seconds further back in third place but Pinot is now just a further three seconds behind in fourth place.
Dan Martin finished 21st, 11'39 behind Yates and moves up to 15th overall. Martin's cousin Nicolas Roche was 64th (24'30) and remains 37th in the GC.
⏪ Relive the last kilometre of Stage 15, the solo win of @SimonYatess and the strong ride by @thibautpinot and @MikelLandaMeana! 💪— Tour de France™ (@LeTour) July 21, 2019
⏪ Revivez le dernier kilomètre de l'Etape 15, la victoire en solitaire de Simon Yates et le numéro de Thibaut Pinot et Mikel Landa ! 💪#TDF2019 pic.twitter.com/nJrA9yWwdf
Yates did not need to worry about the battles unfolding behind him as he took another superb victory.
With his brother Adam's general classification hopes effectively ended in a dismal day on the Tourmalet on Saturday, Simon was free to go stage hunting again.
The 26-year-old was active in a large breakaway which included several riders licking their wounds from the previous day, with Nairo Quintana, Dan Martin, and Romain Bardet all involved.
Geschke attacked on the steep Mur de Peguere around 45km from the finish of the 185km stage from Limoux, but Yates joined him at the summit and they raced clear of the rest.
Yates then struck out for victory early on the final climb, having the power to hold both a surging Mikel Landa and the late attack of Pinot at bay.
But as much as Yates, this was also Pinot's day.
Twenty-four hours after his victory on the Tourmalet, the 29-year-old made clear it is he, and not Alaphilippe, who is France's best chance of ending a 34-year wait for a home winner on the Tour.
He launched his first move seven kilometres from the summit. Only Bora-Hansgrohe's Emanuel Buchmann and Thomas' team-mate Egan Bernal could go with him but Pinot soon shook them both off, catching Movistar's Landa and charging up the mountain to finish 33 seconds behind Yates.
With Monday a rest day, the Tour will now look forward to a fascinating final week.
The belief that Alaphilippe is to be discounted now grows, and only 39 seconds separate Thomas in second and Buchmann in sixth.