Bradley Wiggins has moved within three days of becoming the first British winner of the Tour de France after successfully negotiating the final day in the Pyrenees.
Wiggins began the 143.5km route from Bagneres-de-Luchon to Peyragudes in the yellow jersey for a 10th day and with a lead of two minutes five seconds over Team Sky colleague Chris Froome, with Italian Vincenzo Nibali (Liquigas-Cannondale) 18 seconds further adrift.
No other rider was within five minutes of the triple Olympic champion and Nibali knew he had to make a move, with Wiggins likely to perform better than him in Saturday's penultimate day time-trial.
But Wiggins, with able support from Froome, distanced Nibali on the finishing ascent.
Alejandro Valverde (Movistar) won the stage, Froome was 19 seconds behind in second place, with Wiggins on his wheel in third.
Nibali finished 37 seconds behind in seventh, conceding 18 seconds to Wiggins and falling 2mins 41secs behind.
Ireland’s Dan Martin finished in tenth place, coming home one minute and 11 seconds behind Valverde.
Nicholas Roche was 12th on the stage, and lies just outside the top ten in overall classification in 11th place 12 minutes and 58 seconds.
Friday's 222.5km 18th stage from Blagnac to Brive-la-Gaillarde features three classified climbs, but could end in a sprint finish.
Saturday's penultimate day 53.5km time-trial is the final opportunity to claim time and Wiggins' ability in that discipline suggests he is set to become the first Briton on the podium, with Froome poised to be the second, in the 99 editions of the Tour.
Wiggins added: "The minute we went over the Peyresourde, I pretty much knew that was the climbing done for the Tour and that was an incredible feeling.
"That's where everyone said I was at my weakest, in the mountains."