Chris Froome produced a stunning ride to win stage 10 of the Tour de France and increase his overall lead to nearly three minutes.
Team Sky rider Froome - who led by 12 seconds overnight - broke away with 6.4km left of the first summit finish of this year's race to win emphatically in La Pierre-Saint-Martin.
Richie Porte was second, 59 seconds back, with Nairo Quintana third.
Tejay van Garderen lies second overall, two minutes 52 seconds behind Froome.
Colombian Quintana, a highly regarded climber, had been widely expected to launch a major attack in an attempt to claw back time but he was overtaken by Porte in the final metres of a stage that was nigh on perfect for Team Sky.
It was the fifth stage win of 2013 champion Froome's Tour de France career and puts the 30-year-old in a commanding position with 11 stages remaining.
All of his main rivals lost significant time on a devastating afternoon, with Quintana now three minutes nine seconds behind in the overall standings, Alberto Contador four minutes four seconds back and defending champion Vincenzo Nibali a massive six minutes 57 seconds adrift of the Team Sky rider.
|A good omen?|
|Chris Froome won on Bastille Day in 2013 - a stage that finished on Mont Ventoux - and went on to win the Tour that year.|
"I'm lost for words," said Froome, who was in the news overnight after it was revealed Team Sky believe their computers have been hacked by critics convinced he is using performance-enhancing drugs.
"I could not believe it when I asked the guys to push on a bit and we were hearing on the radio about the big names being dropped. It was textbook from the team and I'm just over the moon to finish it off for them."
Froome could not have made a more decisive statement of his intent to claim his second Tour victory.
He sat in with his Team Sky team-mates while Quintana's Movistar team made the early pace up the 15km climb towards the finish.
A blistering rate soon saw riders disappearing out of the back of the leading groups, while at one point Froome appeared uncomfortable as he hung on at the back of a team-mate's wheel.
|Tough days for Froome's rivals|
|Quintana: "Froome was stronger than me. For now we're going to fight for second place, but we'll also fight for the yellow jersey in the remaining stages."|
|Nibali: "It was difficult, I couldn't follow the pace, I didn't have any puff."|
|Contador: "I don't know why but I couldn't breathe. I felt terrible, really bad."|
|Van Garderen: "I don't think today was my best day but it wasn't all bad."|
But that proved to be nothing more than a ruse, and when Froome made his explosive move there was nothing anybody could do to stay with him - although Quintana's efforts were enough to see him take the white jersey worn by the race's best young rider.
The only danger to the Briton appeared to come from fans as they closed in around him on some of the steeper sections of the climb up the Cote de Cauterets, but they soon cleared and he powered to a potentially decisive finish in this year's race.
Froome's Team Sky team-mate Geraint Thomas is now in fifth place overall after finishing sixth on the stage while fellow Briton Adam Yates crossed the line in seventh after a strong ride up the mountain.
"The plan was to sit behind Movistar and see how many riders we had left," explained Thomas afterwards. "We had four and we all felt good. Froomey said on the radio that he felt good so let's smash it. Personally I felt great and for the team it was even better."
It was Bastille Day in France and the first true day of racing in the mountains as the Tour resumed after Monday's rest day.
There was a lengthy breakaway involving Cofidis's Kenneth Vanbilsen and Bretagne Seche Environment's Pierrick Fedrigo that lasted most of the 167km stage, but which was never going to make it up the final climb.
Vanbilsen picked up all available points at the three category four climbs but with 50 points for the stage winner, Froome now tops the King of the Mountains classification, although second-placed Porte will wear the polka dot jersey on Wednesday.
There was also a change in the points classification for the Tour's leading sprinter, with Andre Greipel overhauling Peter Sagan to reclaim the green jersey after the in-form German took third at the day's intermediate sprint.
More drama could follow on Wednesday when the race continues in the Pyrenees with a 188km stage that includes the infamous Col du Tourmalet climb.
"Challengers were scattered all over the road"
BBC Sport's Matt Slater: "July 14 is when France celebrates the revolutionary storming of a notorious prison, the Bastille; today it was the moment Chris Froome's revolutions probably locked up the yellow jersey for a second time in three years.
"This was a devastating win for Froome and Team Sky, with Grand Tour champions and challengers scattered all over the road up to La Pierre-Saint-Martin. We knew he and his comrades were going well but this was something else.
"What that something is will of course now be the subject of fierce debate. Froome's critics are convinced he is cheating and they claim they have the data to prove it.
"His supporters, however, say those numbers only prove he is a special athlete who has got even better with hard work, careful eating and great coaching. As ever with cycling, absolute agreement is probably impossible."
Stage 10 results
1. Chris Froome (GB) Team Sky 4hrs 22 mins 7secs
2. Richie Porte (Aus) Team Sky +59 secs
3. Nairo Quintana (Col) Movistar +1min 04secs
4. Robert Gesink (Net) LottoNL +1min 33secs
5. Alejandro Valverde (Spa) Movistar +2min 01secs
6. Geraint Thomas (GB) Team Sky Same time
7. Adam Yates (GB) Orica +2min 04secs
8. Pierre Rolland (Fra) Europcar Same time
9. Tony Gallopin (Fra) Lotto +2min 22secs
10. Tejay van Garderen (USA) BMC Racing +2min 30secs
11. Alberto Contador (Spa) Tinkoff - Saxo +2min 51secs
General Classification after stage 10
1. Chris Froome (GB) Team Sky 35hrs 56mins 09secs
2. Tejay van Garderen (US) BMC Racing +2mins 52secs
3. Nairo Quintana (Col) Movistar +3mins 09secs
4. Alejandro Valverde (Spa) Movistar +4mins 01secs
5. Geraint Thomas (GB) Team Sky +4mins 03secs
6. Alberto Contador (Spa) Tinkoff - Saxo +4mins 04secs
7. Tony Gallopin (Fra) Lotto +4mins 33secs
8. Robert Gesink (Net) LottoNL +4mins 35secs
9. Warren Barguil (Fra) Giant +6mins 12secs
10. Vincenzo Nibali (Ita) Astana +6mins 57secs