Simon Geschke clinched a fine solo win on stage 17 of the Tour de France, as Chris Froome maintained his advantage in the general classification after a keen battle between the main contenders.
Wednesday's 161-kilometre stage from Digne-les-Bains to Pra-Loup saw the riders enter the Alps for the first of four mountain stages, and the gruelling trek claimed several casualties including an ill Tejay van Garderen (BMC) - who had started the day third in the GC.
At the head of the race, Geschke (Giant-Alpecin) made a move with 43km left and held off a late fight from Andrew Talansky (Cannondale-Garmin) to secure victory.
Team Sky's Froome matched his rivals step-for-step, and held off a late attack from Nairo Quintana to keep his lead at three minutes and 10 seconds.
Van Garderen was clearly struggling from the off and lost ground on the peloton on the first categorised climb.
The American briefly re-joined the pack, but an attack from Alberto Contador (Tinkoff-Saxo) left him trailing once again and he ground to a halt before being consoled by BMC staff members.
At the front of the race, Geschke decided that a cluster break of 26 riders was not working and went it alone.
By the time he was ascending the category one climb of the Col d'Allors - the highest point of this year's Tour - the German had a gap of 10 minutes to the peloton.
Thibaut Pinot (FDJ) attempted to catch Geschke alone, but the Frenchman's hopes were ended when he crashed going the daunting descent of the d'Allors.
Having negotiated the d'Allors, Geschke had one last climb up into Pra-Loup to negotiate, with enough in reserve to cross the line alone despite Talansky having chipped away at his buffer.
Back in the general classification battle, Contador had to swap bikes on the d'Allors and lost time on his rivals. It proved costly as he slipped behind Geraint Thomas (Sky) in the general classification.
Quintana threatened with a late attack on the Pra-Loup, but Froome went with him wheel-to-wheel and maintained his advantage over the Colombian.