Kazakh Alexey Lutsenko claimed his maiden victory on the Tour de France when he won the sixth stage, a 191-km trek from Le Teil on Thursday as the top guns again delayed the fight for the general classification.
Astana rider Lutsenko, a former Under-23 world champion, prevailed from an eight-man breakaway at the top of Mont Aigoual to add to his 2017 Vuelta stage win.
Spain's Jesus Herrada took second place, 55 seconds behind with Belgian Greg van Avermaet in third, 2:15 off the pace.
Briton Adam Yates retained the overall leader's yellow jersey after staying tucked in the main peloton, which crossed the line with a deficit of 2:53.
"We talked about it in the team bus this morning and we agreed that it was a stage that suited me," said Lutsenko, who broke clear in the punishing ascent to the Col de la Lusette, a 11.7km climb at an average gradient of 7.3%.
Behind him, the main favourites did not use the ascent to test each other, leaving defending champion Egan Bernal's Ineos team to set a moderate pace.
"We knew that this climb was tricky, it was a pretty bad surface. I think we climbed at our own speed and saved energy, we just tried to stay safe," said Ineos domestique Michal Kwiatkowski.
"Everyone is keeping their powder dry and is saving energy for the next days," said Yates, who was never threatened throughout the stage.
Slovenian Tadej Pogacar, who is third overall, suffered an untimely puncture in the climb up to the Col de la Lusette but managed to regain his place in the peloton easily, thanks to the bunch's slow pace.
The only sparkle came in the final metres, when Frenchman Julian Alaphilippe produced a brief attack to regain one second after losing the yellow jersey to Yates following a 20-second penalty for illegal feeding on Wednesday.
Friday's seventh stage is a 168-km ride from Millau to Lavaur, which is expected to favour the sprint specialists.