Chris Froome is set to become the first Briton to win the Tour de France twice after surviving a thrilling attack by Nairo Quintana on Alpe d'Huez.
Team Sky's Froome, 30, led Quintana by two minutes 38 seconds before the penultimate stage but the Colombian rode clear with 9km remaining.
Froome, champion in 2013, responded to limit his losses to just 80 seconds as France's Thibaut Pinot won the stage.
His 72-second lead will not be challenged on Sunday's finale in Paris.
The short 21st stage, which culminates in several laps around the centre of Paris, is largely ceremonial for the yellow jersey, however the stage is expected to end in a bunch sprint with Mark Cavendish chasing a fifth victory on the Champs-Elysees.
That meant Saturday's 110.5km route from Modane was billed as the decider between Froome and his rival Quintana, who had cut the gap by 32 seconds on the previous day's racing.
Quintana is regarded as an expert climber in the mountains, and while Froome clung on to his rival on the first ascent up Col de la Croix de Fer, the Movistar rider proved to have the edge when it came to the arduous 13.9km trek to the top of Alpe d'Huez.
Tour de France overall standings
Chris Froome Team Sky/Britain 81hrs 56mins 33secs
Nairo Quintana Movistar/Colombia +1min 12secs
Alejandro Valverde Movistar/Spain +5mins 25secs
Vincenzo Nibali Astana/Italy +8mins 36secs
Alberto Contador Tinkoff-Saxo/Spain +9mins 48secs
But Quintana will once again finish runner-up to Froome, as he did two years ago, although this is set to be the smallest winning margin since Carlos Sastre beat Cadel Evans by 58 seconds in 2008.
"It's hard to say if this was harder than 2013, but every day was flat out," said Froome, who is one of only two Britons to have won the Tour, along with Sir Bradley Wiggins.
"Next year I'll come back and renew the rivalry with Nairo. He's a great prospect, has a bright future, a great talent who races correctly, making his race at the right moment."