CHRIS Froome has an iron grip on a fourth Tour de France crown after proving bullet proof in the final mountain showdown.
It was the first time in Tour history a stage had finished atop the Col d'Izoard, but Froome ensured it was business as usual in the Alps with a composed display under enemy fire.
Frenchman Warren Barguil delighted the crowd with a second stage win that cemented his place atop the mountains classification.
Down the road the battle for the yellow jersey raged. Romain Bardet and Dan Martin took turns attacking Froome, while the Brit also attacked himself, on the steepest slopes of the Izoard at the end of a rugged 179.5km journey from Briancon.
Froome would finish fourth and even if Bardet's late acceleration trimmed his lead to 23 seconds, the penultimate day time trial - a Froome strength - means it would take a catastrophe for the Team Sky spearhead to lose his grip on a fourth Tour de France.
"It was very, very hard stage with the climb to the finish. I'm happy with today," Froome said.
"I tried to drop Uran and Bardet, but it was virtually impossible today. Of course it would have been nice to take a bit of time, but all in all I'm pretty happy with that. Two seconds over Rigoberto Uran, who I think will be my main rival in the time trial, I'm pretty happy with that."
With only a routine Stage 19 and the Stage 20 time trial remaining, Froome's 23-second lead over Bardet and 29-second advantage on Colombian Rigoberto Uran has all but secured him another yellow jersey.
Team Sky was again imperious, setting a ferocious pace for much of the day. Michael Kwiatkowski was so empty after his effort at the front he literally got off his bike at the side of the road. Mikel Landa, fourth overall, then attacked to draw out Bardet and Uran.
"My teammates did a very good job in the finale to control the break," Froome said.
"It's great having the numbers there to control things and having that card to play with Mikel Landa. I tried to give it a dig behind and I thought that I had a gap, but it looks like Rigoberto Uran brought it back.
"I'm happy to have got through the Alps this year without a problem. They've always been more difficult for me."
Bardet, who has repeatedly rolled the dice in recent days in a bid to break Froome, collapsed in exhaustion at the finish as a swarm of reporters surrounded him.
"I gave everything, I thought I was going to suffocate after the finish line," Bardet said.
"Of course, everybody dreams of big epic attacks but sometimes it's more opportune to wait. There's a difference between dreams and reality.
"I wanted to attack sooner, but there were a lot of Sky riders in the front group and there was a headwind on the climb."
Uran had talked of making similar moves on the Col d'Izoard, but was again unable to take the initiative.
"Attacking Sky with the tempo they were setting - it's difficult to attack a team like that," Uran said.
The stage also confirmed Australian Michael Matthews would win the Tour de France green jersey, barring a mishap, while Orica-Scott's Simon Yates is now almost certain to hold off Louis Meintjes in the battle for the young riders' white jersey.