Vincenzo Nibali claimed his fourth stage success of the 101st Tour de France to all-but seal overall victory.
Nibali (Astana) added victory on the 145.5-kilometre 18th stage from Pau to Hautacam to wins in Sheffield, La Planche des Belles Filles and Chamrousse.
The Italian began the day with an advantage of five minutes 26 seconds and enhanced his lead to a near-unassailable 7mins 10secs with just three stages to go.
Bar a major blow, he will win the yellow jersey in Paris on Sunday, and the battle to join him on the podium intensified on Thursday.
Frenchman Thibaut Pinot (FDJ) was second on the stage, 1min 10secs behind Nibali, to move up to second place overall.
Alejandro Valverde (Movistar), who began the day in second, finished 10th, 1:59 behind, to drop to fourth overall, 7:25 behind Valverde.
Pinot is second by 13 seconds from Jean-Christophe Peraud, who was fourth on the stage, with Valverde two seconds further back.
Friday’s stage is the 208.5km route from Maubourguet Pays du Val d’Adour to Bergerac and expected to suit the sprinters. The podium contenders will have one last chance to gain time in Saturday’s penultimate day time-trial, prior to Sunday’s ceremonial sprinters’ stage on the Champs-Elysees.
A 20-rider breakaway dissolved on the ascent of the day’s third categorised climb, the fabled 17.1km Col du Tourmalet, with Mikel Nieve (Team Sky) and Blel Kadri (AG2R La Mondiale) accelerating to the summit.
Valverde attacked the group of overall contenders on the descent of the Tourmalet.
Nieve attacked on his own on the lower slopes of the 13.6km finishing ascent of Hautacam. Chris Horner (Lampre-Merida) attacked and Nibali went with him, before dropping the American.
The Italian then passed Nieve before going alone, once again demonstrating he is the supreme rider in the race and on course to become the sixth rider to have won all three of the Grand Tours, of France, Italy and Spain.
Who knows how Nibali would have fared had 2013 winner Chris Froome and two-time champion Alberto Contador not crashed out through injury.
Valverde was wavering as his fellow podium contenders forged on ahead of him with around 6km to go.
Pinot drove on with Tejay van Garderen (BMC) and Peraud on his wheel alongside Rafal Majka (Tinkoff-Saxo), who was bidding for the King of the Mountains title. Pinot followed Majka's burst for the line to take some valuable seconds in his battle for second overall.
Peraud was five seconds behind Pinot, with Van Garderen on his wheel, while Valverde dug in in an effort to limit his losses.