Andy Schleck took a brave solo victory on stage 18 of the Tour de France after an attacking ride through the Alps.
The Leopard Trek rider unleashed a 60km attack on his general classification rivals after powering clear on the second climb of the day but narrowly missed out on yellow as Thomas Voeckler hung on with a career-best ride.
The Europcar man rode a canny tactical stage to hold on to the race lead by 15 seconds from Schleck, who took the victory on the day by two minutes and seven seconds over brother Frank (Leopard Trek).
The highest mountaintop finish in Tour history was the scene of incredible drama and likely marked the end of Alberto Contador's (Saxo Bank-Sungard) challenge for yellow, the Spaniard losing 3:50 as he cracked on the Alpine climb.
Cadel Evans (BMC) who was third home, led the chasing bunch up the steep ramps of the hors-categorie test with leader Voeckler seemingly content to let others do the work in shutting down the gap.
Contador was finally distanced as Evans drove the gap to Schleck down under three minutes on the brutal climb with a titanic effort, a dig matched by Voeckler who, although distanced, punched the air as he crossed the line knowing he was safe in yellow.
The penultimate mountain test condensed the leaderboard yet further at the sharp end, moving Frank Schleck to just 1:08 off Voeckler, while Evans, despite losing a place, is 1:12.
Mark Cavendish (HTC-Highroad) finished the stage in a gruppetto of 88 riders but was judged to have finished outside of the time limit, the organisers docking the Manxman 20 points from his green jersey tally.
The situation means that Cavendish has a lead of 15 points over Jose Joaquin Rojas (Movistar), the competition likely to be decided on the Champs-Elysees in Paris.
Cavendish said: "It's disappointing. We thought we were way out of the time limit with quite a long way to go but it was a lot closer and had we known it might have made a difference.
"We just have to think about tomorrow now."
Despite a tough day in the mountains ahead there was no respite from the flag as the 18th stage got off to another fast start.
An early intermediate sprint point after 46.5km meant the bunch kept the speed high, yet in a move that was to initially benefit green jersey-holder Mark Cavendish (HTC-Highroad), a 16-man breakaway broke clear just one kilometre from the sprint.
The strong group, including Nicolas Roche (Ag2r) and Joost Posthuma and Maxime Monfort (Leopard Trek) opened out an advantage that peaked at just over nine minutes as three more riders bolstered their ranks.
Europcar tapped out a tempo in support of Voeckler on the hors-categorie Col d'Agnel which rose to a Tour-record altitude of 2744 metres.
Maxim Iglinskiy (Astana) looked the strongest of the break as he attacked over the top of the 'roof of the Tour', taking a 5,000 euro prize and pushing on down the descent on a dig that would stand him in good stead later in the race.
There were a number of raised eyebrows in the bunch as Andy Schleck attacked out of the bunch on the steeper ramps of the day's second climb, a sustained effort that saw the Luxembourg rider distance his rivals.
Tactics came into play as first Poosthuma then Monfort dropped back out of the break and buried themselves in aid of their Leopard Trek team leader.
A tense game of cat and mouse came into play in the bunch behind as the final climb loomed large, all the while the gap growing out to the younger Schleck.
As Schleck continued up the Galibier with Iglinskiy and Roche in toe, arguments broke out in the chasing group as Voeckler and Evans disagreed over who should take up the chase.
Evans finally cracked and put in a dig that was swiftly closed down, but the emphasis was on the Aussie who put in a huge effort on the front while the likes of Samuel Sanchez (Euskaltel) and white jersey holder Rigoberto Urán (Team Sky) were dropped from the group
Schleck shed the attentions of Maxim Iglinskiy (Astana) and Nicolas Roche (Ag2r) in the closing kilometres as the crowd closed in and held on to take an emotional win.
Further back Rein Taaramae (Cofidis) put in a gutsy ride to claim the white jersey while Jelle Vanendert (Omega Pharma-Lotto) and Cavendish took advantage of the work of others to maintain polka dot and green respectively.