SAINT-LARY-SOULAN, France -- Tadej Pogacar said it was going to be the hardest day of the Tour de France.
He made it look easy.
The race leader finished ahead of his rivals and took a major step toward defending his title with a perfectly executed 17th-stage win in the Pyrenees on Wednesday.
The 22-year-old Pogacar made his move with 8.5 kilometers to go on Col de Portet when he powered past previous leader Anthony Perez on his way to victory at 2,215 meters above sea level -- the highest stage finish this year.
"It has been a fantastic day. To win in the yellow jersey is something I can't describe," Pogacar said.
Jonas Vingegaard stayed on Pogacar's wheel, with Richard Carapaz close behind, but Rigoberto Uran, who was previously second in the general classification, was unable to keep pace and dropped back to fourth overall.
David Gaudu gave chase to keep alive hopes of a French win on Bastille Day.
Pogacar didn't look concerned, however, as he settled into a three-way fight for the line, roared on by noisy roadside fans on the cloud-kissed mountain.
Carapaz attacked with 1.4 kilometers to go, and Pogacar followed. Vingegaard appeared to be dropped but fought back, and Pogacar accelerated when he needed to win the sprint. Carapaz finished third.
"Only Jonas and I cooperated to put some distance between us and the rest of the GC favorites," Pogacar said. "At some point, Jonas came by and told me that he thought Carapaz was bluffing. I knew it also -- that's tactics in pro cycling. When Carapaz attacked, I was very driven to catch him and hold his wheel. I just sprinted out on the last 150 meters."
It was Pogacar's first stage win since claiming the yellow jersey on the eighth stage.
The defending champion stretched his lead in the general classification to 5 minutes, 39 seconds over Vingegaard, with Carapaz a further four seconds behind.
Pogacar joked Tuesday that he wished he hadn't cycled Wednesday's route in advance as it would be better not to know what was to come.
"I know the road, but you need the legs to climb it," the Slovenian rider said before the start of the unforgiving 178.4-kilometer route that ended with three major obstacles in a row: the 1,569-meter Col de Peyresourde, the 1,580-meter Col de Val Louron-Azet and the Col du Portet.
There were several skirmishes at the head of the peloton before Perez, Lukas Postlberger, Danny van Poppel and Dorian Godon carved a narrow lead on the flat route before the mountains. They were joined by Anthony Turgis and Maxime Chevalier.
Steven Kruijswijk dropped out after nearly an hour of cycling. The Jumbo-Visma team said Kruijswijk felt ill during the rest day Monday and that his condition hadn't improved. It left the team with just four riders: Vingegaard, Wout van Aert, Sepp Kuss and Mike Teunissen.
The six breakaways stretched their lead to eight minutes after 60 kilometers and maintained a good advantage as they approached Col de Peyresourde. Turgis was first to the summit.
Turgis, Perez and Godon dropped Postlberger, Chevalier and van Poppel on the climb to Col de Val Louron-Azet, and Perez made his move 5.5 kilometers before the summit, which he reached 10 seconds before the chasing Godon.
Godon hit a top speed of 52 mph on the downhill to catch Perez with 22 kilometers to go. Turgis was just over a minute behind, while Pogacar and the peloton remained just under four minutes off the pace.
Perez made another break with 13.5 kilometers to go, while many riders were struggling on the steep 16-kilometer climb up Col de Portet. Nairo Quintana's hopes of challenging for the polka dot jersey ended when he dropped back 15 kilometers before the summit. The Colombian rider won at Col de Portet three years ago.
The strain was evident on Perez's face as he remained on his own with 9.2 kilometers remaining.
Pello Bilbao led the yellow-jersey group with Pogacar ever closer. Once Pogacar made his move, there was only going to be one winner.
Thursday will be the final day in the mountains before the riders can look forward to easier rides on the way to Sunday's finish on the Champs-Elysees in Paris. The 18th stage from Pau features another mountaintop finish at Luz Ardiden after a long climb up the formidable 2,115-meter Col de Tourmalet.
"Tomorrow is going to be one of the biggest stages of the tour," Vingegaard said. "And hopefully I'll be there. I'm going to do my best."