Bradley Wiggins of Britain took another step towards securing his maiden Tour de France crown after a 16th stage won in stylish fashion by Frenchman Thomas Voeckler on Wednesday.
Yellow jersey holder Wiggins and Chris Froome repelled two attacks by Vincenzo Nibali on the fourth and final climb to come over the finish alongside his Italian rival and Sky teammate 7min 09sec behind Voeckler.
Defending champion Cadel Evans of BMC finished at 11:56 behind Voeckler and nearly five minutes behind Wiggins' group after being dropped for good on the Col du Peyresourde.
It later transpired that Evans had suffered stomach problems two hours before the race. Now 8:06 behind Wiggins, his title defence is now virtually over.
"I didn't think it would affect me in the race but obviously that's not my normal level and it's pretty much the Tour de France over for me," said the Australian.
For Wiggins, it is one less rival to look out for on the final climbing stage Thursday, which finishes on the summit of Peyragudes.
He warned: "The one thing I keep saying is that no one has it easy out there. We're all in the same boat and we all have to do the same course and tomorrow is another day."
But with Nibali still third at 2:23 and with a 3:23 lead on fourth-placed Belgian Jurgen Van den Broeck, it is now effectively a three-man race to Paris. The Sicilian did not make his move until they had ridden on to the 9.5 km-long hike to the summit of the Col de Peyresourde.
An acceleration gave the Italian a lead of about 50 metres. But Froome, who so often this race has looked more comfortable than Wiggins on the long climbs, easily countered.
He brought Wiggins on his wheel level with Nibali, who took a breather, had a think and then attacked again just before the summit. This time, it was Wiggins who brought the Sicilian to heel.
"We were very comfortable there. I don't think he was really going anywhere," added Froome.
Wiggins was quick to share out the plaudits with his Sky teammates.
"The team rode fantastically well again and we've created the ideal scenario by putting even more time into Cadel Evans, and although we weren't able to get rid of Nibali - who is very strong - it was a great day," said Wiggins.
Voeckler, meanwhile, grabbed his second stage win of the race and the fourth of his career after leaving breakaway companion Brice Feillu of Saur-Sojasun behind with 22 km remaining and 7km from the summit of the Col du Peyresourde.
Danish pursuer Chris Anker Sorensen came over the finish 1:40 adrift, giving the Europcar rider plenty of time to savour his second victory in Luchon, two years after winning stage 15 in 2010.
It was also the fifth victory of the race for the hosts, following wins for Thibaut Pinot (FDJ), Pierre Rolland (Europcar) and Pierrick Fedrigo (FDJ).
"I'm very proud of what I did today. It's the kind of cycling I like and the kind of attack I grew up watching on the television when I was young," said Voeckler, who took over the King of the Mountains polka dot jersey with a four-point lead on Swede Fredrik Kessiakoff.
"Now I have to try and recover as much as possible, with a really long massage and then try and do it all again tomorrow."
The 17th stage on Thursday is a 143.5 km ride from Luchon to the summit of Peyragudes and is the last climbing stage of the race.
And for Nibali, it could be the last chance for glory on the race.
"I wanted to try to win today but it wasn't so easy after the 38-man breakaway escaped," added Nibali, a former Tour of Spain winner who has also been third in the Giro d'Italia.
"But I will try again tomorrow."