Tour de France leader Chris Froome has survived a thrilling Col d'Izoard climb while Australia's green jersey favourite Michael Matthews remains well clear after a thrilling 18th stage.
Three-time winner Froome held on to his yellow jersey as Frenchman Romain Bardet's hopes of mounting a decisive attack fizzled out, while Matthews remains 160 points clear of his nearest rival Andre Greipel.
With Bardet's countryman Warren Barguil producing a stunning burst on the brutal 14km climb to the summit to claim victory, all eyes were on what was going on back down the twisting road.
Team Sky's Froome, who began the final big day of climbing in the Alps with a 27-second lead over Bardet and Rigoberto Uran, was pressurised on the unrelenting slopes as Bardet's AG2R La Mondiale team tried to loosen his grip.
But Froome crossed the line just behind Bardet, who he now leads by 23 seconds, with Uran - now 29 seconds behind - also in close support, and now only an extraordinary meltdown or a crash seem likely to stop the Briton taking a fourth Tour title.
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Barguil sealed the polka dot climber's jersey with a brilliant ride up the iconic Izoard climb, which was staging a summit finish for the first time in Tour history.
Matthews has been rooming with Sunweb teammate Barguil and was ecstatic at the team's success.
"It's truly incredible, for Warren and for the team," the Australian told cyclingnews.com
"Now four stage wins in this Tour de France, and I think we just sealed both jerseys. So in one bedroom in our hotel we have four stage wins and two jerseys in the one room.
"[The green jersey] is something I've dreamed about since I started cycling, basically, watching guys like Robbie (McEwen) winning the green, and all the other Australians: Cookie (Baden Cooke) winning the green, Stewie (Stuart O'Grady) winning the green ... now it's my opportunity to go for it."
Friday's stage is a relatively straightforward 222-km ride south towards the coast before Saturday's time trial in Marseille, where Froome is likely to extend his lead over his rivals for the yellow jersey.
