Dutchman Wilco Kelderman took over as leader of the Giro d'Italia as the fearsome Stelvio climb blew the race apart during a brutal stage 18 battle.
Kelderman (Sunweb) began the day 17 seconds behind long-time race leader Joao Almeida, whose hopes of wearing the 'maglia rosa' all the way to Milan were shattered.
Portuguese Almeida cracked on the steep and twisty 24km Stelvio climb, losing three minutes before the summit as Kelderman took over as the virtual leader.
Kelderman was also distanced on the day's big climb, however, dropping 47 seconds behind Britain's Tao Geoghegan Hart, who was taken up the climb by Ineos Grenadiers team mate Rohan Dennis, and his Sunweb team mate Jai Hindley.
After a freezing descent through the snowfields and ahead of the day's final climb to the finish of the 207km Queen's stage, Kelderman looked to be going backwards.
But he had just enough left in the tank to take the maglia rosa, although Saturday's climbs to Sestriere now look as though they will prove decisive.
Australian Hindley took the stage win just ahead of Geoghegan Hart, two minutes 18 seconds ahead of Kelderman, and will are both breathing down his neck in the battle for the pink jersey.
Following the race, it was announced that Italian cyclist Matteo Spreafico has been provisionally suspended after he twice tested positive for a banned substance.
The UCI says Spreafico, a 27-year-old riding in the Giro for the Vini Zabu–KTM team, returned adverse analytical findings for Enobosarm, also known as ostarine, on 15 and 16 October.
A statement on the UCI’s website said: "Italian rider Matteo Spreafico has been notified of two adverse analytical findings for Enobosarm (ostarine) in two samples collected during the Giro d’Italia on 15 and 16 October 2020.
"The rider has the right to request and attend the analyses of the B samples.
"In accordance with the UCI Anti-Doping Rules, the rider has been provisionally suspended until the adjudication of the affair.
"At this stage of the procedure, the UCI will not comment any further on this matter."