Chris Froome tightened his grip on the yellow jersey in an epic 18th stage of the Tour de France despite receiving a 20-second penalty for breaking feeding rules.
The 28-year-old Briton ran out of energy on the second of two ascents of the legendary Alpe d'Huez and had to ask team-mate Richie Porte to collect a gel from the Team Sky car with 5km to go.
He continued on to take seventh place on the stage and although he was later sanctioned for illegally eating within the final 10km, he still extended his overall lead over Alberto Contador (Saxo-Tinkoff) to 5min 11sec after the Spaniard was dropped on the final climb and lost 57 seconds.
The memorable, 172.5km stage was won in magnificent style by breakaway rider Christophe Riblon (Ag2r-La Mondiale), who will enter French cycling folklore after an heroic ride in which he snatched victory from Tejay van Garderen (BMC) inside the final 3km.
Brilliant Riblon wins
Riblon had been dropped by his fellow escapee midway up the second ascent of Alpe d'Huez and trailed by 40 seconds at one point, but stormed back brilliantly and overtook the helpless American in the dying stages.
Moreno Moser (Cannondale), who had also been part of the day's breakaway, was also dropped on the final climb but hung on to take third, while Nairo Quintana (Movistar) out-sprinted Joaquim Rodriguez (Katusha) to finish fourth.
That duo had been climbing in a group with Froome and Porte, but they attacked when Froome began to wilt and, being no immediate danger on the general classification, the Team Sky pair did not give chase.
Contador was already a minute back down the road by that point after being dropped 11km from the finish line.
The Saxo-Tinkoff rider had put pressure on Froome throughout the day, first by sending team-mates ahead of the peloton and then attacking at a furious pace on the descent of the Col de Sarenne, in between the two climbs of Alpe d'Huez.
But that exertion appeared to drain him of energy and the two-time winner was unable to put up any sort of fight when Froome mounted his own attack on the lower slopes of the last climb.
Up ahead, Van Garderen had tailed off both Riblon and Moser - his fellow survivors of the day's nine-man breakaway - and looked on course for a famous win.
But at the same time as he began to fade, Riblon found a second wind and showed marvellous spirit to swiftly cut the gap and win by almost a minute.
Stage 18 result
1 Christophe Riblon (Fra) Ag2r-La Mondiale, 4:51:32
2 Tejay Van Garderen (USA) BMC, +59sces
3 Moreno Moser (Ita) Cannondale, +1:27
4 Nairo Quintana (Col) Movistar, +2:12
5 Joaquim Rodriguez (Spa) Katusha, +2:15
6 Richie Porte (Aus) Team Sky, +3:18
7 Chris Froome (GB) Team Sky, same time
8 Alejandro Valverde (Spa) Movistar, +3:22
9 Mikel Nieve (Spa) Euskaltel-Euskadi, +4:15
10 Jakob Fuglsang (Den) Astana, st
11 Alberto Contador (Spa) Saxo-Tinkoff, +4:15
1 Chris Froome (GB) Team Sky, 71:02:19
2 Alberto Contador (Spa) Saxo-Tinkoff, +5:11
3 Nairo Quintana (Col) Movistar, +5:32
4 Roman Kreuziger (Cze) Saxo-Tinkoff, +5:44
5 Joaquim Rodriguez (Spa) Katusha, +5:59
6 Bauke Mollema (Ned) Belkin, +8:58
7 Jakob Fuglsang (Den) Astana, +9:33
8 Michael Rogers (Aus) Saxo-Tinkoff, +14:26
9 Michal Kwiatkowski (Aus) Saxo-Tinkoff, +14:38
10 Alejandro Valverde (Spa) Movistar, +14:56
- Green (points classification): Peter Sagan (Svk) Cannondale
- White (best young rider): Nairo Quintana (Col) Movistar
- Polka dot (mountains classification): Chris Froome (GB) Team Sky