Adam Yates surrendered the yellow jersey as pre-race favourite Primoz Roglic assumed control of the Tour de France on a thrilling stage nine to Laruns.
It was a Slovenian one-two as Roglic's good friend Tadej Pogacar beat the Jumbo-Visma rider on the line at the end of a ferocious 153km stage from Pau which found Yates' breaking point after four days in yellow.
The Bury rider lost touch with the main group of contenders on the Col de Marie Blanque as Roglic and Pogacar broke free on the final climb of the day along with defending champion Egan Bernal and Mikel Landa.
Up ahead Marc Hirschi was looking to finish off a 90km solo ride with the stage win but he would be caught inside the final two kilometres. He recovered to contest the sprint but came in third.
That still proved significant as he denied fourth-placed Bernal bonus seconds on the line, leaving the Colombian 21 seconds down in second place overall. The French duo of Guillaume Martin and Romain Bardet are third and fourth at 28 and 30 seconds respectively.
Yates finished in a group some 54 seconds after the leaders to send him tumbling down the general classification, having found his limits after a tough fight to keep yellow on Saturday.
The Mitchelton-Scott rider came into the Tour focused on stage wins after illness hampered his preparations, and as he now finds himself down in eighth place, 62 seconds off the lead, he will revert to that plan after Monday's rest day.
"I did my best," Yates said. "I knew coming into the race I wasn't 100 per cent. I gave everything I could to hang on. I think we can be pretty proud of what we did. We'll freshen up with the rest day and go after some stages.
"I did what I could but there were just some guys with better condition than me. It is what it is.
"There are a lot of stages in the last week that suit me quite well so we'll see what we can do. It's a big honour to ride in yellow and it was fun while it lasted."
Pogacar was among the contenders to lose 81 seconds in crosswinds on Friday, but has looked determined to correct that mistake in the days since.
The 21-year-old recovered 40 seconds with a late dig on Saturday and his attack lit up this stage – delivering the rewards as he became the Tour's youngest stage winner since a certain Lance Armstrong back in 1993.
It was almost all undone as the UAE Team Emirates rider touched wheels with Roglic at the top of the Marie Blanque in a moment's carelessness, but both stayed upright.
"I made a little mistake," Pogacar said. "I thought maybe I dropped everyone but actually Roglic was coming on my left. I was a bit (careless). We touched wheels but everything was OK...
"After that hard day, to win the stage is incredible."
Roglic will now enjoy Monday's rest day with the yellow jersey on his back after a week in which the collective strength of the Jumbo-Visma team – winners of three stages between Roglic and Wout van Aert – only underlined his status as favourite.
"It's beautiful," the 2019 Vuelta winner said. "This is the first time that I have had (yellow) and I think everyone is dreaming about it when you start being a rider.
"I'm super, super happy, especially for the guys who again did an amazing job so this is also for them."
"We race with a mission to try to win it in Paris so we need to maintain focus and do our best everyday."
Bernal remains the primary threat as the Ineos Grenadiers rider eyes a tough final week in the Alps.
"I was feeling good (on the last climb) and that gave me a bit of confidence for the next part of the race," the 23-year-old said.
"I know that I lost time with Roglic and Pogacar but I should be patient and stay focused and try to go day by day because this is a race of three weeks and it will be hard in the last six days."