The Briton cracked with less than five kilometres to go on the second trip up the mountain's 21 hairpin bends but sent team mate Richie Porte to fetch some food and the Australian nursed Froome to the finish 3:18 behind Riblon, who became the first Frenchman to win a stage in this year's race.
Chris Froome moved closer to a maiden Tour de France title with an awe-inspiring victory on top of the intimidating Mont Ventoux, pulling away from his rivals in brutal fashion seven kilometres from the finish on Sunday.