The Briton has a virtual extra advantage as he is expected to beat his rivals in the final time trial on Saturday.
Unlike on the 33 other appearances of the Izoard on the route, Thursday's 179km stage from Briancon actually ends on the summit - ensuring a lung-bursting sprint.
Time and again on the slopes of the Galibier, Froome's Spanish team-mate Mikel Landa, chased down attacks by Bardet and Martin, keeping the Sky leader out of trouble. The team's really struggling today.
"I don't think my vocabulary is extensive enough to describe it really". At their quickest, the riders descended at 75 kph. Urán, a Colombian completes the leading quartet, 29 seconds off the pace. "It's still all to race for". Bardet is also 27 seconds behind.
It is unlikely any of the contenders will be able to escape on the Col de Vars, but the Izoard will be another story.
"I can't complain, it was a perfect day for me".
Roglic attacked solo six kilometres from the summit of the Galibier, the second of two hors categorie climbs on a testing day, and made it pay to deliver Slovenia's first Tour de France stage win.
"It's a shame, the 34-year-old Spaniard said".
Froome finished 1 minute and 13 seconds after Roglic in a group with Rigoberto Uran and Romain Bardet, who climbed to second and third overall respectively.
Chris Froome fought off fierce crosswinds to protect the yellow jersey but Martin lost 51 seconds on the leader as his Quick-Step team-mates failed to help him on several late breaks as the peloton split in the final 20k. My legs felt good so why not keep everyone in check? The riders will start the stage with tired legs after Wednesday's ride―Thursday's stage has the potential to break a rider completely.
British sprinter Dan McLay of Fortuneo-Oscaro abandoned on the Col du Telegraphe, passing the lantern rouge as last man in the Tour to Team Sky's Luke Rowe. But that discipline isn't Aru's forte-unlike Froome.
The Matthews-Kittel battle could come down to the final stage, the ceremonial ride into Paris on Sunday.
"I lost time today".
"I'm still in the clouds, I've left the earth", said Barguil. The officials saw that. I have no regrets.
For the first time since 1992, all five of France's mountain ranges - the Vosges, the Jura, the Pyrénées, the Massif central and the Alps - will feature, while three of the five mountain stages include altitude finishes.
Bardet said he was hoping to leave Froome behind, too.