Bradley Wiggins is poised to become the first Briton to win the Tour de France after victory in Saturday's time trial.
Only an accident, stopping Wiggins, 32, from finishing Sunday's final stage in Paris, will prevent him from winning.
He now leads Chris Froome by three minutes, 21 seconds after beating his Team Sky team-mate in the 53.5km race.
"Today was a superb performance," said Wiggins. "I really wanted to get out there and finish with a bang. Fortunately I managed to do that."
He added: "It's the stuff of dreams to win the final time-trial and seal the Tour.
"I was thinking of my wife, children, grandfather, nan with about 20 kilometres to go. It sounds cheesy, but your whole life is for this and the reason I got into cycling as a kid was today."
It was a stunning performance from the Londoner who finished one minute and 16 seconds ahead of fellow Brit Froome in a blistering time of 1:04.13 to win his second stage of this year's Tour, the stage 19 time-trial to Chartres.
"As we saw he's stronger than me," said Froome. "I'm very happy. The [Team Sky] goal this year was to win the Tour with Bradley. To be second is an added plus."
Team Sky principal Dave Brailsford briefly let his guard down after the race. "It is a very proud moment," he said. "Bar anything silly we can start thinking about winning this race now."
"I would never have said we could do it if I didn't believe that. We had done our homework, we knew what Bradley was capable of and what the British team is capable of. Today is all about Bradley and what a fantastic champion.
"As we know, we are lucky to have Chris and Bradley in the same team. But this was a tour that suited Bradley, he's climbing well and his time trials are off the scale. That shows why we stuck with Bradley.
"It`s a lot easier to manage two good riders than two bad ones."
Wiggins, a three-time Olympic track champion, began the individual time-trial from Bonneval with an advantage of two minutes five seconds over Froome and he cemented his reputation as the best time-trial cyclist in the world with victory.
He now heads into Sunday's 120km 20th stage from Rambouillet to the Champs-Elysees in Paris knowing he should return home victorious.
Froome is also on the verge of history - no Briton has finished on the Tour podium in 98 previous editions, with Wiggins' 2009 fourth place equalling Robert Millar's 1984 best. Now there are set to be two.
Italy's Vincenzo Nibali is set to complete the top three despite finishing 3'38" behind Wiggins on stage 19.
The Liquigas rider is 6'19" adrift of Wiggins in the overall standings, almost four minutes clear of fourth-placed Belgian Jurgen van den Broeck.
The challenge of defending champion Cadel Evans faded in the Pyrenees mountains and the Australian, who has been troubled by illness, fell further back on the time trail.
Despite the final riders going out at three minute intervals, Evans was overtaken by his BMC Racing team-mate Tejay van Garderen with 20km of the time trial remaining and took 5'54" longer than Wiggins to drop once place to seventh, 15'51" back.
As well as being the display which all but secured the yellow jersey, Wiggins' was a performance which augured well for the Olympic road race on 28 July and the time-trial on 1 August.
Wiggins, Froome and Garmin rider David Millar, who all won stages on this year's Tour, will combine to try and help world road race champion Mark Cavendish win the road race in London in seven days.
Wiggins and Froome will then compete for gold in the time trial.
Before that though Cavendish, who won stages two and 18, will be seeking to complete a stunning Tour de France for Britain on Sunday's processional stage, usually contested by the sprinter.
The 27-year-old Manxman has completed the Tour three times and won on the Champs-Elysees on each occasion - in 2009, 2010 and 2011 - and it is likely that Team Sky will be leading out Cavendish on the French capital's most famous boulevard.
Stage 19 result:
1. Bradley Wiggins (GB) Team Sky 1:04'13"
2. Christopher Froome (GB) Team Sky @ 1'16"
3. Luis-Leon Sanchez (Spa) Rabobank @ 1'50"
4. Peter Velits (Svk) Omega Pharma @ 2'02"
5. Richie Porte (Aus) Team Sky @ 2'25"
Overall standings after stage 19:
1. Bradley Wiggins (GB) Team Sky 84hrs 26mins 31 secs
2. Christopher Froome (GB) Team Sky @ 3'21"
3. Vincenzo Nibali (Ita) Liquigas @ 6'19"
4. Jurgen van den Broeck (Bel) Lotto Belisol @ 10'15"
5. Tejay van Garderen (USA) BMC @ 11'04"