BRIANCON, France (Reuters) - Tour de France leader Chris Froome remained rock-solid on a thrilling Col d'Izoard climb won in audacious fashion by Warren Barguil on Thursday and now looks unstoppable in his bid to claim a fourth title in Paris.
Fans wedged onto the 2,360m sun-bleached landscape roared home Barguil who became the fifth Frenchman to win the iconic climb which had posed the last serious threat to Froome.
It was not the story the home fans craved though.
They had imagined Romain Bardet leaving Froome in his wake and snatching the yellow jersey on the last day in the Alps.
The AG2R La Mondiale rider did beat Team Sky's Froome over the line at the end of a 179km stage culminating in a brutal 14km ascent to the lunar-like Izoard summit finish.
But his third place, behind Sunweb's Barguil and Colombian Darwin Atapuma, only allowed him to shave four seconds off Froome's 27-second lead as the British rider finished just behind in fourth place with other GC rival Rigoberto Uran fifth.
One-time race leader Fabio Aru's hopes evaporated as he suffered and slipped from fourth to fifth on the leaderboard behind Froome's strong-finishing team mate Mikel Landa.
"I gave it my all," 2016 runner-up Bardet, who had set out to become France's first Tour winner since 1985, said. "I risked everything. I have nothing to regret."
After some early wobbles Froome has looked in control in the Alps and with just Friday's straightforward 222km ride south followed by a time-trial in Marseille before the ceremonial roll into Paris he looks armour-plated for the third year in a row.
The Briton leads Bardet by 23 seconds and Uran by 29.
"For sure it would have been amazing to have won on the most iconic climb of the race but my goal is the yellow jersey," Froome said. "The hardest part of the Tour is behind now.
"The top three are all within 30 seconds. Rigo seems to be the biggest threat for the time trial, but there are still two days of racing, so anything can happen."
Everything that happened during the ride from Briancon, including the leg-sapping Col de Vars climb, was a prelude to the eagerly anticipated final act on Izoard -- a climb that is as much part of Tour folklore as Mont Ventoux.
Kazakh Alexey Lutsenko, part of a 50-strong breakaway group earlier in the day, crested the Col de Vars in the lead and was the first to attack on Izoard before he was caught by Atapuma with 6km remaining.
But it was to be Barguil's day as he sewed up the polka dot jersey, timing his move to perfection to burst past Atapuma 1.5km from the finish and power to the line.
"I feel like I've left the ground and I'm floating above the clouds," an emotional Barguil, who has wrapped up the polka dot jersey, said. "It's a dream, it's unbelievable."
Back down the road the tension mounted as Bardet, whose AG2R team had set a rip-roaring pace in a bid to shed Froome's Sky team mates, finally attacked. But he could make no impression.
In actual fact Froome, with Landa just ahead of him, launched his own attack and briefly dropped Bardet and Uran before they hauled themselves back to the man in yellow.
Bardet crossed before Froome for a small time bonus but it was of little consequence.
Barring a calamity all that remains now is for Froome to seal the deal with a stage win that has been elusive this year and it could come around the streets of Marseille on Saturday.
Reporting by Martyn Herman; editing by John Stonestreet and Toby Davis