BMC's Greg Van Avermaet became the third man to claim the yellow jersey in the first week of the 2016 Tour de France, after winning stage five from Limoges to Le Lioran.
The most punishing stage yet, saw riders take on six categorised climbs, five of which came in the final 75km of the 216km stage.
A breakaway group of nine riders attacked early in the day, and out of the remnants of that group, Van Avermaet, Thomas de Gendt (Lotto-Soudal) and Andriy Grivko (Astana) made their own break with around 90km remaining and at no point looked like being reeled in by the peloton.
With Grivko distanced, van Avermaet pounced for victory on the penultimate climb up the Col de Perthus, ditching de Gendt and then easing over the final climb of the day up the Col de Font de Cere to ride into yellow by more than five minutes from Julian Alaphilippe and Alejandro Valverde.
Van Avermaet wins Belgian battle to move into yellow
Around the 30km to go mark, the peloton were too far behind to mount a serious push for victory, and the counter-attacking group which included Rafal Majka was not closing on the front two.
Van Avermaet looked the stronger of the two riders, and that showed when he finally made the break for home, eventually winning by more than 2minutes 35seconds from his fellow Belgian who clung on for second on the stage.
The defeat will taste a little sweeter for de Gendt, who accumulated enough mountain points over the day's climbing to pass Jasper Stuyven in the King of the Mountain classification, meaning he is now the proud owner of the polka dot jersey.
The 1-2 Belgian finish was the first time this had been achieved at the Tour since 2007 when Gert Steegmans led home Tom Boonen at a sprint finish into Gent.
Sagan and Nibali dropped on first major ascent
There was also drama unfolding further back in the race, with former yellow jersey holder Peter Sagan and 2014 champion Vincenzo Nibali distanced as soon as the pace picked up on the penultimate climb.
Sagan's climbing struggles were expected, and he will now concentrate on re-claiming the green jersey as well as winning more stages.Nibali however, will be disappointed with his climbing efforts and is now almost certainly out of the running for the overall crown.
Another former champion who continued to struggle was Alberto Contador, with the Spaniard losing more time to his potential rivals.
Chris Froome, Nairo Quintana and Fabio Aru all remain unscathed and are in the top ten placings overall, each of them 5minutes 17seconds behind van Avermaet, who is extremely unlikely to be a major factor once the real climbing gets underway.