Thomas De Gendt produced a career-defining ride to take victory on the highest mountain-top finish in Grand Tour history at the Giro d'Italia.
The Belgian (Vacansoleil-DCM) took the win on stage 20 at the Passo dello Stelvio and wrote his name into the history books with an epic ride, finishing 55 seconds ahead of his closest rival and vault up to fourth in the overall standings.
The 25-year-old was on the offensive all day, attacking first on the steep ramps of the Mortirolo before pushing onwards again on the lead-up to the 2,757-metre final climb.
Damiano Cunego (Lampre-ISD) and Mikel Nieve (Euskaltel-Euskadi) were next home, unable to live with the accelerations of De Gendt.
Behind the leading contenders scrambled to cover off the threat up the road, Ryder Hesjedal (Garmin-Barracuda) forced to push onwards after team-mate Christian Vande Velde had buried himself on the lower slopes of the Stelvio.
On the snow-lined roads Michele Scarponi (Lampre-ISD) was the first to attack, the 2011 winner pushing onwards only to be overhauled by race-leader Joaquim Rodriguez (Katusha), who re-extended his lead after taking fourth.
The Spaniard's late surge also had dire consequences for Team Sky's Mark Cavendish, the Brit forced to relinquish the red points jersey by a single point to the climber.
With just the final Milan time trial remaining, Rodriguez holds a 31-second advantage over Hesjedal, who still sits in the box seat with his superior time trialling ability.
Scarponi clung onto the final step of the podium with De Gendt threatening just 27 seconds back heading into the 30-kilometre test.
Team Sky's Colombian pairing Rigoberto Uran and Sergio Henao battled hard on the stage to claim eighth and ninth on the line, the result dropping Uran out of the top five to seventh overall.
Earlier 17 riders went clear in the day's break on the Passo del Tonale, a significant move with the top four men on the GC all having riders in the break.
Oliver Zaugg (RadioShack-Nissan) and Matteo Carrara (Vacansoleil-DCM) pushed on up the brutally steep slopes of the Mortirolo, with Carrara soon to be joined by team-mate De Gendt.
In a surprise move, Rodriguez put in a speculative attack, firing a warning shot to test the legs of his rivals, yet with 61km to go the Spaniard knocked off the move and resumed tempo.
Behind a gruppetto including Cavendish began to form heading out of Tirano at the foot of the Mortirolo after what had been a big effort to stay in up to that point.
Panic stations
Sitting eighth coming into the stage, De Gendt sprung clear alongside team-mate Matteo Carrara, eventually linking up with Cunego and Nieve to drive out a dangerous advantage.
Behind the favourites began to look at each other, the gap rolling out to around four minutes before order was temporarily restored, yet De Gendt kicked on again, taking a further minute to cement his insurmountable advantage.
After being pulled back from the break Vande Velde set about riding on the front in service of Hesjedal on the lower slopes of the Stelvio but the gap held steady.
The race will be decided on Sunday in a shoot-out between Rodriguez and Hesjedal with the winner taking home the maglia rosa in Milan.
