Roglic arrived at the Megeve summit finish-line three minutes adrift of the winner in the main pack with the surviving overall contenders all taking the same time.
But the Slovenian former ski jumper was badly grazed after a fall and he lost a key teammate as Jumbo-Visma’s Steven Kruijswijk pulled out early on.
The Dutchman was third in last season’s Tour de France and suffered a dislocated shoulder here, appearing disconsolate at the roadside two weeks ahead of the Grande Boucle.
In the same downhill crash Bora lost three men including Emanuel Buchmann, who came fourth on the 2019 Tour.
The day started with raised eyebrows as British team Ineos general and reigning Tour de France champion Egan Bernal pulled out of the race with a bad back.
“This is my first pro win, so I want to keep something of it for myself,” said the 23-year-old Kamna, who dropped everyone in a powerful escape group including Julian Alaphilippe and Michal Kwiatkowski.
There were around 40km of climbs on this run through southeastern France’s Haute-Savoie region, known for its mountains, lakes and Evian mineral water, and which culminated with a view of Mont Blanc at the finish line.
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