After nearly six hours in the saddle and almost 19 kilometres of relentless climbing, Froome pulled clear of Nairo Quintana just as they were passing the memorial to Tom Simpson on Mont Ventoux, which marks the spot where the first ever Briton to wear the yellow jersey died on this climb in the 1967 Tour.
As he crossed the line with one arm raised aloft, Froome extended his overall lead to more than four minutes, with Bauke Mollema and Alberto Contador unable to keep up.
“Every cyclist would dream of winning a stage like this,” Froome said. “It really is amazing. This has to be the biggest win of my career.”
The Team Sky rider poured so much effort into the win that, so close to the spot where Simpson expired while operating on a cocktail of brandy and amphetamines, Froome had to be given oxygen at the finish.
“I can’t remember ever needing oxygen before but I hope it’s relatively normal given that it’s a full-gas effort up to the finish,” he said. “I’m feeling much better now.”
The Bastille Day stage was designed to be one of the epics in Tour history.
First there was a 221km ride south from Givors just to get to Mont Ventoux, before the 21.5km ascent of ‘God’s Tomb’, at an average gradient of 7.5 per cent to the summit 1,912 metres above sea level.
If that was not enough, riders had to tackle sweltering temperatures on this unforgiving mountain, where vegetation soon gives way to bare rock offering no shade.
Sylvain Chavanel shot off the front dreaming of Bastille Day glory and a first French win of this Tour, while Peter Sagan, content with intermediate sprint points with which to protect his green jersey, quickly dropped back, even pulling a wheelie for the cameras when he was caught by the pack.
Sky continued to set the pace in the peloton and did not blink as further attacks went off the front.
Quintana’s was the first meriting serious attention as the Colombian went with 13km to go. Froome upped the pace with Richie Porte and only Contador could stay with the Sky pair, the tension rising with the two main rivals together.
But with 7.2km remaining, Porte whispered a few words to Froome and he was gone, dropping Contador without even climbing out of the saddle.
He was quickly on the wheel of Quintana and briefly took a 14-second lead before allowing the Colombian to draw level, the two sharing the road as the relentless climb continued out of the trees and on to Mont Ventoux’s upper reaches.
As they passed Simpson’s memorial, Froome pulled away, with Quintana giving up the chase.
Ireland’s Dan Martin remains in 11th in the general classification, after finishing 14th yesterday.
Nicolas Roche is 38th overall after finishing 54th yesterday.